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HEATING  AND  VENTILATION. 


PART     I. 


INSTRUCTION     PAPER 


AMERICAN      SCHOOL     OF      CORRESPONDENCE 

[OHARXERKD    BT    THE    tJOMMONVVEALTH    OF*    M  A  SSACHOSETTs] 

BOSTON,     MASSACHUSETTS 
U  .    S  .   A  . 


Prepared  By 

Charlks  Tv.  HriiBARD,   M.K., 

OK 
S.    HOMKR    WooniiKIDGE    COMPANY, 

Heating,  Ventilation  and  Sanitary  Kngineers. 


Copyright  igo2,bf 

AMtritan  School  of  Co^-resfondnn* 

*  Boston,  Mass. 


HEATING  AND  VENTILATION. 


SYSTEMS  OF  WARMING. 

Any  system  of  warming  must  include,  first,  the  combustion 
of  fuel  which  may  take  place  in  a  fireplace,  stove,  steam  or  hot- 
water  boiler  ;  second,  a  system  of  transmission,  by  means  of  which 
the  heat  may  be  carried,  with  as  little  loss  as  possible,  to  tlie 
place  where  it  is  to  be  used  for  warming,  and  third,  a  system  of 
diffusion,  which  will  convey  the  heat  to  the  air  in  a  room  and  to 
its  walls,  floors,  etc.,  in  the  most  economical  Avay. 

Stoves.  The  simplest  and  cheapest  form  of  heating  is  the 
stove.  The  heat  is  diffused  by  radiation  and  convection  directly 
to  the  objects  and  air  in  the  room,  and  no  special  system  of  trans- 
mission is  required.  The  stove  is  used  largely  in  the  country 
and  is  especially  adapted  to  the  warming  of  small  dwelling  houses 
and  isolated  rooms. 

Furnaces.  Next  in  cost  of  installation  and  simplicity  of 
operation  is  the  hot-air  furnace.  In  this  method,  the  air  is  drawn 
over  heated  sui'faces  and  then  transmitted  through  pipes,  while  at 
a  liigh  tempe.ature,  to  the  rooms  where  heat  is  required.  Fur- 
naces are  used  largely  for  warming  dwelling  houses,  also  churches, 
halls  and  schoolhouses  of  small  size.  They  are  more  costly  than 
stoves,  but  have  some  advantages  over  that  form  of  heating. 
They  require  less  care,  as  several  rooms  may  be  warmed  from  a 
single  furnace  ;  and,  being  placed  in  the  basement  all  dust  from 
coal  and  ashes  is  kept  from  the  looms  above. 

In  construction  a  furnace  is  a  large  stove  with  a  combustion 
chamber  of  ample  size  over  the  fire ;  the  whole  being  enclosed  in 
a  casing  of  sheet  iron  or  brick.  The  bottom  of  the  casing  is  pro- 
vided with  a  cold-air  inlet,  and  at  the  top  are  pipes  which  connect 
with  registers  placed  in  tlie  various  rooms  to  be  heated.  Cold 
fresh  air  is  brought  from  out  of  doors  through  a  pipe  or  duct 
called  the  "cold-air  box;"  tl lis  air  enters  the  space  between  the 
casing  and  the  furnace  near  tlie  bottom  and  in  passing  over  the 


iir.A'nNc  AM)  \  i:\'ni.A'n«>\. 


hot  siirfart's  of  tlu*  liif  pot.  iiiid  comlmsti  >ii  (iliiunher,  becomes 
hoatod.  It  tlu'n  lisos  throut^h  the  \v:inn-air  pipes  at  tlio  to[)  of 
tlu'  I'su^inn'  and  is  disi-har^ed  tliioUL;li  tin;  registers  into  the  rooms 
i\ho\G. 


As  the  warm  air  is  taken  from  the  top  of  the  furnace,  cold 
air  flows  in  through  tlie  cold-air  box  to  take  its  phice.  The  air 
for   ht-atinj'  tlie  rooms  does  not  enter  the  combustion  chamber. 


HEATING  AND  VENTILATION. 


Fig.  1  shows  the  general  arrangement  of  a  furnace  with  its  con- 
necting pipes.  The  cokl-air  inlet  is  seen  at  the  bottom  and  the 
hot-air  pipes  at  the  top;  these  are  all  provided  with  dampers 
for  shutting  off  or  reguhiting  the  amount  of  air  flowing  through 
them.  Tjie  feed  or  fire  door  is  shown  at  the  front  and  the  ash 
door  beneath  it;  a  water  pan  is  placed  inside  the  casing  and  fur- 
nishes moisture  to  the  warm  air  before  passing  into  the  rooms; 
water  is  either  poured  into  the  pan  through  an  opening  in  the 
front,  provided  for  this  purpose,  or  is  supplied  automatically 
through  a  pipe. 

The  fire  is  regulated  by  means  of  a  draft  sHde  in  the  ash 
door  and  a  cold- air  or  regulating 
damper  placed  in  the  smoke- 
pipe.  Clean-out  doors  are  placed 
at  different  points  in  tlie  casing 
for  tlie  removal  of  ashes  and 
soot.  Furnaces  are  made  either 
of  cast  iron,  or  of  wrouglit  iron 
plates  riveted  together  and  pro- 
vided with  brick-lined  fire  pots. 

One  great  advantage  in  this 
method  of  warming  comes  from 
the  constant  supply  of  fresh  air 
which  is  required  to  bring  tlic 
heat  into  the  rooms.  While  thisl 
is  gi-eatly  to  be  desired  from  a 
sanitary  standpoint  it  requires  a  ^^^'  ^' 

larger  amount  of  fuel  than  would  otherwise  be  necessary,  for  heat 
is  required  to  Avarm  the  fresli  air  from  out  of  doors  up  to  the  tem- 
perature of  the  rooms,  in  addition  to  that  lost  by  leakage  through 
walls  and  windows. 

A  more  even  temperature  may  be  maintained  in  this  AA^ay 
than  by  the  use  of  stoves,  owing  to  the  greater  depth  and  size  of 
the  fire,  which  causes  it  to  be  more  easily  controlled.  When  a 
building  is  placed  in  an  exposed  location,  difficulty  may  be  experi- 
enced at  times  in  warming  certain  rooms,  depending  upon  the 
direction  of  the  wind ;  this  may  be  overcome  to  a  large  extent  by 
a  proper  location  of  the  furnace  ami  the  exercise  of  suitable  care 


111. Al'IXCi  AND  VENTILATION. 


in  ruiiiiiiiLr  till'  I'omitH-tiiiLr  |n]u's.      Tliis  will    Im-   t;ikiMi  up  hitn-   in 

llu»    (It'siLTll    of     lltMtillLlf   SVStlMUS. 

Direct  Steam  Heating.  Diifct  stciiii  licnt  iiii^^  is  used  in  all 
I'hussi's  ol  liuiKliui^s,  Imth  l»_v  itsrit"  and  in  coinhinat  ion  with  dllicr 
systems.  The  first  eos to f  installation  is  i^n-i-atcr  than  I'm-  liirnace 
lieating  Imt  the  anionnt  of  lUcl  rc.|nirf(|  is  less,  as  no  ontsidc  air- 
supply  is  neeessary.  It'  us('<l  I'di-  wanninu;-  hospitals,  schoolhouscs 
«tr  otlu-r  huildiuiifs  where  ventilation  is  desired,  it  must  he  supple- 
mented by  some  other  means  for   jnox  idini;-  warm    fresh  air.     A 

system  of  dii-eet 
steam  liealing  eon- 
sists  of  a  furnace 
and  Ixtiler  for  the 
eotnhnstion  of  fuel 
and  tin;  generation 
of  steam  :  a  system 
of  [)ipes  for  con- 
veying the  steam 
to  the  radiators  and 
for  retui-niuLC  the 
water  of  condensa- 
tion to  the  hoilei-; 
and  i-adiatoi's  or 
coils  placed  in  the 
I'ooms  for  (lil1'usini( 
the  heat. 

Various  types 

of  hoilers  are  used,  depending  upon  the  size  and  kind  of  l)uilding 
to  l>e  warmed.  Some  foiin  of  cast  iron  sectional  boiler  is 
commonly  used  for  dwelling  houses,  while  the  tu])ular  or  water- 
tuljc  boiler  is  more  usually  employed  in  larger  buildings.  Where 
the  boiler  is  used  for  boating  pur[)oses  oidy,  a  low  steam  pres- 
sure of  from  2  to  10  pounds  is  carried  and  the  condensation 
flows  back  by  gravity  to  the  boiler  which  is  })la(;ed  ])elow  the 
lowest  radiator.  When,  for  any  reason,  a  higher  pressui-e  is 
required,  the  steam  for  the  heating  system  is  made  to  pass  tliiough 
a  reducing  valve  and  the  condensation  is  returned  to  the 
boiler    by    means    of    a    pump   ov    return    trap.      TIkj   methods  of 


HEATING  AND  VENTILATION. 


making  tlie  pipe  connections  between  the  boiler  and  radiators 
vary  for  different  conditions  and  in  different  systems^  of  heating. 
These  will  be  taken  up  later  under  the  head  of  design. 

Direct  radiating  surface  is  made  up  in  different  ways :  Fig  2 
shows  a  common  form  of  cast  iron  sectional  radiator;'  these  can  be 
made  up  in  any  size  depending  upon  the  height  and  number  of 
sections  used.  Fig.  3  is  made  up  of  fertical  wrought  iron  pipes 
screwed  into  a  cast  iron  base  and.  is  a  very  efficient  form.  Fig.  4 
shows  a  type  of  cast  iron  wall  radiator  wHch  is  often  used  where 
it  is  desired  to  keep  the  floor  free  from  obstruction.  Fig.  5  is  a 
special  form  of  dining-room  radiator  provided  with  a  warming 
closet.     Wall  and  ceiling  coils  of  wrought  iron  pipe  are  often  used 


Fig.  4. 

in  school  rooms,  balls  and  shops  or  where  the  appearance  is  not 

objectionable. 

Indirect  Steam.  This  system  of  heating  combines  the  advan- 
tages of  both  the  furnace  and  direct  steam  but  is  more  expensive 
to  install.  The  amount  of  fuel  required  is  about  the  same  as  m 
the  case  of  furnace  heating.  Instead  of  placing  the  radiators  in 
the  rooms,  a  special  form  of  heater  is  placed  beneath  the  floor  ai» 
encased  in  galvanized  iron  or  brickwork.  A  cold-air  box  is  con- 
nected with  the  space  beneath  the  heater  and  w^rm-air  pipes  at 
the  top  are    connected  with  registers  in  tlie    floors  or  walls  as 


lli:.\llN(i    AM)   \  KNTILA'I'ION 


alivsulv  iU'soiil>od  (ov  funuK-i's.  A  se^Ktratc  licaici-  may  ho  pro* 
viiU'il  for  o;u'h  ivgister  if  the  rooms  are  lar^o,  or  two  or  uu)re 
iv*'isttM-s  may  bo  coniuH-tfd  with  the  same  lieatcr  if  tlic  hoiizoiital 
runs  of  pipe  aro  short.  Fii^.  •>  sliows  a  sct'tioii  ihioni^li  a  heater 
arranired  for  introilueing  hot  air  into  a  room  throiii;h  a  lh»or 
ivi^istor  ami  Fig.  7  shows  the  same  type  of  lieater  ooiineited  witli  a 

wall  register.    The 

cold-air  box  is  seen 

at  tlie  bottom  of  the 

casing,  and  the  air 

ill  passing  through 

the  s[)aees  between 

the  sections  of  the 

heater,    becomes 

wanned   and   rises 

to  tlie  rooms  above. 

Different  forms 

of  indirect  heaters 

^^S»  5.  f^j.g  sliown  in  Figs. 

8  and  9.     Several  sections  connected  in  a  single  group  are  called  a 

"Stack."     Sometimes  the  stacks  are  encased  in  brickwork  built 

up   froui    the    basement 

floor  iiKStead  of  galvan-  " T'""' ^-— '=^gMiBapjh_  _    '^i 

ized  iron  as  shown  in 
the  cuts.  This  methoil 
of  heating  provides  fresh 
air  for  ventilation,  and 
for  this  reason  is  espe- 
cially adapted  foi-  school- 
houses,  hospitals, 
churches,  etc.  As  com- 
pared witli  furnace  heat- 
ing it  has  the  advantage 
of  lieing  less  affected  by  outside  wind  pressure,  as  long  runs 
of  horizontal  i>ipe  aie  avoided  and  the  heaters  can  be  placed 
near  the  registers.  In  a  htrge  building  where  several  fur- 
naces would  Ix;  re(juired,  a  single  boiler  can  be  used  and  the 
uuudiur  of  stiicks  increa.sed  to  suit  the  existijig  conditions,  thus 


HEATING  AND  VENTILATION. 


making  it  necessary  to  run  but  a  single  fire.  Another  advantage 
is  the  hirge  ratio  between  the  lieating  and  grate  surface  as  com- 
pared with  a  furnace,  and  as  a  result  a  large  quantity  of  air  is 
warmed  to  a  moderate  temperature  in  place  of  a  smaller  quantity 
heated  to  a  much  higher  temperature.  This  gives  a  more  agree- 
able quality  to  the  air  and 
renders  it  less  dry.  Direct 
and  indirect  svstems  are  often 
combined,  thus  providing  the 
living  rooms  with  ventilation 
while  the  hallways,  corridors, 
etc.,  have  only  diiect  ladia- 
tors  for  warming. 

Direct" Indirect  Radiators. 
A  direct-indirect  radiator  is 
similar  in  form  to  a  direct 
radiator  and  is  placed  in  a 
room  in  tlie  same  manner. 
Fig.  10  shows  the  general 
form  of  this  type  of  radiator 
and  Fig.  11  shows  a  section 
through  the  same.  The  shape  of  the  sections  is  such,  that  when 
in  place,  small  flues  are  formed  between  them.  Air  is  admitted 
through  an  opening  in  the  outside  wall  and  in  passing  upward 


Fig.  7. 


Fig.  8. 

through  these  flues  becomes  heated  before  entering  the  room.  A 
switch  damper  is  placed  in  the  duct  at  the  base  of  the  radiator  so 
that  the  air  may  be  taken  from  the  room  itself  instead  of  from 
o  it  of  doors  if  so  desired. 


10 


IIKATINU  AND  VENTll.A'riON. 


Direct  Mot  Water.  Tliis  syslcin  is  similar  in  const  iiifl  ion 
to  one  for  direct  sloiun,  except  thai  liol  water  Hows  lluouij^li  the 
pij.rs  ami  nuliatoi-s  instead  of  steam,  ll  Js  largely  used  for  the 
warmini'    of   dwelling   houses   to  which  it  is    especially  adapted 


Fiir.  9. 

owin<T  to  the  ease  with  which  the  temperature  of  the  water  can  he 

regulated. 

Where  steam  is  used  the  radiatoi\s  arc  always  at  practically  the 

same  tempera+^^ure,  and  regulation 
must, he  secured  ])y  shutting  off 
steam  and  turning  it  on  at  inter- 
val?  depending  on  the  outside 
tempeiature ;  while  with  hot  water, 
the  radiators  can  be  kept  turned 
on  all  the  time,  and  regulation 
secured  hy  varying  the  tempera- 
ture of  the  water  flowing  through 
them. 

There  are  two  distinct  systems 
of  circulation  employed;  one  de- 
jl^^^^  pending  on  the  difference  in  tem- 
|)(nature  of  the  water  in  the  siip- 
nlv  iiiid  return  pip(;.s,  called 
"gravity  circulation;"  and  an- 
other, where  a  pump  is  used  to 
force  the  water -through  the  mains, 


Fig.  11. 


called  ''forced  circulation."     ITie  former,  is  used  for  dwellings 
and    other  buildings   of  ordinary  size,   and   tlie   latter   for   large 


HEATING  AND  VENTILATION. 


11 


buildings,  and  especially  where  there  are  long  horizontal  runs  of 

pipe. 

For  o-ravity  circulation  some  form  of  sectional  cast  iron  boiler 
is  commonly  used  although  wrought  iron  tubular  boilers  may  be 
employed  if  desired.  In  the  case  of  forced  circulation  a  heater 
designed  to  warm  tlie  water  by  m^ans  of  live  or  exhaust  steam  is 
often  used.     A  centrifugal  or  rotary  pump  of  the  type  shown  in 


Fig.  10. 


Fig.  12  is  best  adapted  to  this  purpose;  this  pump  may  be  driven 
by  an  electric  motor,  or  a  steam  engine,  as  most  convenient.  Fig. 
13  shows  the  general  form  of  a  hot- water  radiator,  which  is  similar 
to  those  used  for  steam,  except  the  sections  are  connected  at  the 
top  as  well  as  at  the  bottom;  this  is  shown  by  the  cap  over  the 
opening  at  the  top  of  the  end  section,  which  does  not  Appear  on 
the  steam  radiator  shown  in  Fig.  2.  A  system  for  hot-water 
heating  costs  more  to  install  than  one  for  steam  as  the  radiators 


\'2 


MK  \  ri\(.    w  i)  \  i:\  rii.A  riox. 


Iiavf  t4>  he  larp'i-  and  tlir  |>i|>ini,''  ol"   l.irL,'«M-  si/.c  and    iiioi'.'  carcl'iilly 
•;nul«Ml. 

Indirect  Hot  Water.  Iliis  is  iisf<l  uiidt'i'  tlic  siune  coiuli- 
tioiis  as  indiivct  stoaiii,  and  llic  licalcis  used  arc  similar  to  tliosc 
ahvady  doserilH-d.      SpL'ciiil  alLciitii)ii  is  n-ivcii   lo  tin-  foi m  of  the 

sfclidiis  ill  order  lliut 
t lit'ic  inav  l)(^  an  even 
distiil)ntio!i  of  wati'i' 
tlirougli  all  jiaiLs  of 
lliom.  Figs.  14  and 
1.)  show  typical  liot- 
watiT  ladiators  foi'  in- 
direct work.  As  the 
stacks  are  placed  in 
the  l)asement  of  a 
hiiildiiig,  and  only  a 
short  distance  ahove 
the  hoiler,  exti'a  large 
pi[)es  must  be  used  to 
secure  a  ])ro[)er  cir- 
c  u  1  a  t  i  o  n  .  for  the 
*'  h  ('  a  d  "  ])roducing 
How  is  small.  'I'he 
stack  casings,  cold  and 
warm-air  pipes  and 
registers  ai'C  the  same 
as  in  steam  heating. 
I'^xhaust  steam  is  used  for  heating  in  con- 
nection with  jiower  plants,  as  in  factoiies  and  shops  or  in  olFice 
luiildings  which  have  their  own  lighting  plants.  Thcie  are  two 
methods  of  using  exhaust  steam  for  heating  purposes.  One  is  to 
carry  a  hack  jjressure  on  the  engines  of  from  5  to  10  pounds, 
depending  on  the  length  and  size  of  tlu^  pipe  mains,  and  the  other 
is  to  use  some  form  of  ''vacuum' system  "  which  consists  of  a  pump 
or  ejector  attached  to  the  returns  from  the  ladiators ;  this  draws 
the  steam  through  the  radiatois  and  tends  to  reduce  the  back 
pressure  on  tlie  engines  mthcr  than  to  increase  it. 

Where  the  fust  method  is  used,  and  a  back  pressure  carried, 


Exhaust  Steam. 


HEATING  AND  VENTILATION. 


13 


either  the  holier  pressure  or  the  cut-off  of  the  engines  must  he 
increased  to  keep  the  "mean  effective  pressure"  the  same  and  not 
reduce  tlie  horse-power  delivered.  In  general  it  is  more  econom- 
ical to  utilize  the  exhaust  steam 
for  heating.  There  are  in- 
stances, however,  where  the  re- 
lation between  the  quantities  of 
steam  required  for  heating  and 
for  power  ai-e  such,  especially 
if  the  engines  are  run  condens- 
ing, that  it  is  better  to  throw 
the  exhaust  away  and  heat  with 
live  steam.  Where  the  vacuum 
method  is  used  these  difficulties 
are  avoided,  and  for  this  reason 
it  is  coming  into  more  common 
use.  If  the  condensation  from  the  exhaust  steam  is  returned  to 
the  boilers  the  oil  must  first  be  removed ;  this  is  usually  accom- 
plished by  passing  the  steam  throngh  some  form  of  grease  ex- 
tractor as  it  leaves  the  engine.     The    water   of  condensation  is 


Fig.  12. 


Fig.  14. 


then  passed  tlirough  a  separating  tank  before  it  is  delivered  to 
the  return  pumps.  It  is  better  to  remove  a  portion  of  the  oil 
before  the   steam   enters  the  pipes  and  radiators,  else  a  coating 


n 


llKATIMi   AM)   VKXTILATJON. 


will   he   lin-nu'd   on    llicir   iniicr  .siirfiin-s    wliicli    will    rcdiicr    tluMr 
lu'aliiiL;  I'fluit'iuv. 

Forced  Blast.  This  iiiotiuul  oi  heating,  in  (liiTeroiit  forms, 
is  used  for  tin*  wanuinn'  of  fai'tories,  schools,  churches,  theatres, 
halls  or  any  large  building  where  good  ventilation  is  desired. 
The  air  for  \v:irniing  is  drawn  or  fon-ed  through  a  heater  of  spetnal 
design,  and  disrhargctl  l.y  a  fan  or  blower  into  ducts  which  lead  to 
registei's  placed  in  the  rooms  to  be  warmed.  The  heater  is  usually 
made  up  in  sections  so  that  steam  may  be  admitted  to  or  shut  off" 
from  any  section  independently  of  the  othei-s,  and  the  temper- 
ature of  the  air  regulated  in  this  manner.     Sometimes  a  by-[)ass 


Fiir.  15. 


damper  is  attached,  so  that  i)art  of  the  air  will  pass  through  the 
heater  and  part  around  or  over  it  ;  in  tliis  way  the  pi'Oportions  of 
cold  and  lieated  air  may  be  so  ailjusted  as  to  give  the  desired 
temperature  to  the  air  entering  the  rooms.  These  forms  of  regu- 
lation are  common  where  a  l)lower  is  used  for  warming  a  single 
room  as  in  the  ciise  of  a  church  or  liall ;  but  where  seveial  looms 
are  warmed,  as  in  a  schoolhouse,  it  is  customary  to  use  the  main 
or  primary  heater  at  the  blower  for  warming  the  air  to  a  given 
temperature,  (somewhat  l)elow  that  which  is  actually  required) 
and  to  su])plement  this  by  j)lacing  secondaiy  coils  or  heaters  at 
the  bottoms  of  the  flues  leading  to  the  different  rr)oms.  By 
means  of  this  arrangement  the  temperature  of  each  room  can  be 
regulated  indei)endently  of  the  others.  The  so-called  double 
duct  .system  Is  sometimes  employed.     In  this  case  two  ducts  are 


HEATING  AND  VENTILATION. 


15 


carried  to  each  register,  one  supplying  hot  air  and  the  other  cold  or 
tempered  air,  and  a  damper  for  mixing  these  in  the  right  propor- 


Fijr  16. 


tions  is  placed  in  the  Hue  below  the   register.     Fig.  16  shows  a 
coiinnon  form  of  the  lieater  used  in  connection  with  a  fan  ;  this  is  en- 


!♦*> 


Ill-  \  ri\(.     \\  1>   \  lATll. A  rioN, 


ruiifil  ill  luMN  V  sliri'i  iron  or  ItiiikworU,  ;m<l  is  so  coniUM^ted  with 
the  fan  that  thi'  air  is  dniwii  or  forcrd  throiiL^h  thii  spaces  betwiH'U 
the  hot  pipos  aiul  tlius  Iktohu's  hi'ali'd.  Kii,'.  1  7  rt'pn'soiits  the  usual 
Unux  of  fain  wheel  used  for  heating  and  ventilating  work  ;  this  is 
enclased  in  a  steel  plate  casing  with  inlet  openings  at  llie  sides 
and  a  iliseharge  outlet  at  the  outer  I'llge  of  the  fan.  A  common 
arnmgement  of  fan  and  Jieater  is  shown  in  Fig.  18.  The  arrows 
indieate  the  eoKl  air  entering  the  heater  and  the  discharge  from 
the  fan  is  through  the  circular  opening  at  the   top  of  the  casing. 


This  fan   is  -^i' 


Fig.  17. 


r  driven  by  a  direct  connected  engine. 
Electric  motors  and  steam 
engines  ai'e  both  used  for  this 
purjxjse  and  may  be  either 
belted  or  direct  connected. 

Fig.  19  shows  a  fan  and 
heater  arranged  for  a  double 
duct  system.  A  portion  of 
the  air  passes  through  the 
heater,  the  top  of  which  can 
be  seen  where  the  casing  is 
broken  away ;  the  remainder 
of  the  air  passes  partly 
through,  and  partly  over  the 
heater,  depending  upon  the 
position  of  the  by-pass  dam- 
per above.     The  temperature 


of  the  air  in  the  upper  duct  is  therefore  less  than  that  in  the 
lower,  and  the  two  can  be  mixed  at  the  registers  as  required.  In 
Fig.  20  is  shown  a  type  of  fau  called  the  "  cone  fan."  This  is 
usually  placed  in  an  opening  in  a  brick  wall  and  discharges  air 
from  it«  entire  peiimeter  into  a  room  called  a  "plenum  "  chamber, 
with  which  the  various  distributing  ducts  connect. 

Electricity.  Tnless  electricity  is  produced  at  a  very  low 
cost,  its  use  for  heating  residences  or  large  buildings  is  not  piacti- 
cable.  It  has  however  quite  a  field  of  usefulness  in  the  heating 
of  small  offices,  bath  rooms,  cold  corners  of  rooms,  electric  cars, 
etc.,  and  is  often  used  in  rooms  which  cannot  Ije  reached  by  steam 
or  warm-air  pi[>es. 


HEATING  AND  VENTILATION. 


17 


It  lias  the  special  advantage  of  being  instantly  available,  and 
the  amount  of  heat  may  be  regulated  at  will. 

The  heaters  are  perfectly  clean,  do  not  vitiate  the  air  and  are 
portable.  They  are  usually  arranged  in  sections  so  that  the 
amount  of  heat  can  be  regulated  as  desired.     They  are  made  up 


Fig.  18. 

of  resistance  coils  embedded  in  asbestos  or  some  other   form   of 
non-conducting  material. 

Figs.  21,  22  and  23  show  different  forms  of  electric  radiators  ; 
Fig.  22  is  designed  especially  for  car  heating. 

PRINCIPLES  OF   VENTILATION. 

Closely  connected  with  the  subject  of  heating  is  the  problem 
of  maintaining  air  of  a  certain  standard  of  purity  in  the  various 
buildings  occupied. 

The  introduction  of  pure  air  can  only  be  done  properly  in 
connection  with  some  system  of  heating,  and  no  system  of  heating 
is  complete  without  a  supply  of  pure  air,  depending  in  amount 
upon  the  kind  of  building  and  the  purpose  for  which  it  is  used. 

Composition  of  the  Atmosphere,     It  has  already  been  stated 


l^ 


IlKAIMNC    AM)  VKN'TII, A'IMON. 


in  tlu>  iiistnu'tioii  pajicr  '>ii  ('luMiiistrv  that  at iiiiispliciic-  aii-  is  not 
a  sii'.iplt'  siil)st;iiu't'  Imt  a  iiu'clianiral  ini\(iirf.  ()\yg<'ii  and 
nitwi^on,  tho  })riiu-i|tal  rdustituiMils,  are  iJirsciit  in  wiy  nearly  the 
j)ix)iK>rtii>ii  oi  DUO  part  of  oxygi-n  to  foni-  parts  of  nitrogen  by 
woijjht.  CarlMJiiie  aeid  giis,  tlie  ])n)aucl  of  all  eonilnistion,  exists 
in  the  proportion  of  3  to  h  \y.ivts  in  10,0()0  in  the  o[)en  eoimtry. 
Water  in  tlie  form  of  vapor,  varies  greatly  witli  the  temperatnre, 
and  the  exposure  of  tlie  air  to  open  bodies  of  water.  In  addition 
to  the  alM»ve,  there  ai-e  generally  ])resent,  in  varial)le  bnt  exceed- 
ingly small  (piantities,  ammonia,  sulphuretted  hydrogen,  sulphuric, 
sulphurous,  nitric  and  nitrous  acids,  floating  organic  and  inorganic 
matter  ami  local  imj»urities.  Air  also  contains  ozone  which  is  a 
I>eculiarly  active  form  of  oxygen,  and  lately  a  new  constituent 
called  arcfon  has  bt'cn  discovered. 


Fig.  19. 

Oxygen  is  <^ne  of  the  most  important  elements  of  the  air, 
so  far  as  both  heating  and  ventilation  are  concerned.  It  is  the 
active  element  in  the  chemical  process  of  combustion  and  also  of 
a  somewhat  similar  process  which  takes  place  in  the  respiration 
of  human  }>eings.  Taken  into  the  lungs  it  acts  upon  the  excess 
of  carlwn  in  the  blood,  and  possibly  upon  otlier  ingredients,  form- 
ing chemical  comf)OMnds  which  are  thrown  ofT  in  the  act  of  resper- 
ation  or  bn-athing. 

Nitrogen.  The  principal  bulk  of  the  atmo.sphere  is  nitrogen, 
which    exists  uniformly  diffusefl  with  oxygen  and   carbonic   acid 


HEATING  AND  VENTILATION. 


19 


gas.  This  element  is  practically  inert  in  all  processes  of  combus- 
tion or  respiration.  It  is  not  affected  in  composition,  either  by 
passing  through  a  furnace  during  combustion  or  through  the  lungs 
in  the  process  of  respiration.  Its  action  is  to  render  the  oxygen 
less  active  and  to  absorb  some  part  of  the  heat  produced  ])y  the 
process  of  oxidation. 


Fig.  20. 

Carbonic  Acid  Gas  is  of  itself  only  a  neutral  constituent  of 
the  atmosphere,  like  nitrogen,  and  contrary  to  the  general  im- 
pression its  presence  in  moderately  large  quantities  (if  uncombined 
with  other  substances)  is  neither  disagreeable  nor  especially  harm- 
ful. Its  presence  in  the  air,  however,  provided  for  respiration, 
decreases  the  readiness  with  which  the  carbon  of  the  blood  unites 
with  the  oxygen  of  the  air,  and  therefore,  when  present  in  sufficient 
quantity  may  cause  indirectly,  not  only  serious,  but  fatal  results. 


20 


iii:.\  ii\«;  AND  \  i:n  riLAi'ioN, 


Tho  iviil  h;inn  of  :i  vitiiitod  utniosplicro  is  c;iusod  In  its  oilier 
roiistitiiont  «;as«'s  and  I>y  the  minutu  oi-u^iiiisms  which  are  [)ro(liu;ed 
in  the  pnvess  of  i-espiialion.  It  is  known,  howevei-,  that  these 
other  impurities  exist  in  IImmI  proportion  to  the  ainnnnl  of  i-arhonic 
aeid  present  in  an  atniospliere  vitiatc'd  hy  resi)iration.  Therefore, 
as  the  rehitive  proportion  t)f  earhonic  acid  may  he  easily  deter- 
mined by  experiment,  the  fixing  of  a  standard  limit  of  the  amount 


FiLr.    21. 


in   which  it  may  he  allowed,   also  limits    the    amounts  of  other 
impurities  whicli  are  found  in  combination  with  it. 

Wlien  carbonic  acid  is  present  in  excess  of  10  parts  in  10,000 


Fi^.  iiii. 


parts  of  air,  a  feeling  of  weariness  and  stuffiness,  general  13^  accom- 
panied by  a  lieadache,  will  be  experienced;  while  with  even  8 
[)arts  in  10,000  parts  a  room  would  be  considered  close.  For 
general  considerations  of  ventilation  the  limit  should  be  placed  at 
G  to  7  parts  in  10,000  thus  allowing  an  increase  of  2  to  3  parts 
over  that  present  in  outd')Oi'  air  which  may  be  considered  to 
contain  four  ])arts  in  10,000  under  ordinary  conditions. 

Analysis  of  Air.     The  amount  of  carbonic  acid  present  in 


HEATING  AND  VENTILATION.  21 


the  air  may  be  readily  determined,  with  sufficient  accuracy  for 
practical  purposes,  in  the  following  manner : 

Six  clean,  dry  and  tightly  corked  bottles,  containing  respec- 
tively 100,  200,  250,  300,  350  and  400  cubic  centimeters,  a  glass 
tube  containing  exactly  15  cubic  centimeters  to  a  given  mark,  and 
a  bottle  of  perfectly  clear,  fresh  lime-water  make  up  the  apparatus 
required.  The  bottles  should  be  filled  with  the  air  to  be  exam- 
ined by  means  of  a  hand-ball  syringe.  Add  to  the  smallest  bottle 
15  cubic  centimeters  of  the  lime-water,  put  in  the  cork  and  shake 
well.  If  the  lime-water  has  a  milky  appearance  the  amount  of 
carbonic  acid  will  be  at  least  16  parts  in  10,000.  If  the  contents 
of  the  bottle  remains  clear,  treat  the 
bottle  of  200  cubic  centimeters  in 
the  same  manner ;  a  milky  appear-  L^tvi^w^ytj^: 
ance  or  turbidity  in  this  would  mdi-  ^•*'"  ""-' 
cate  12  parts  in  10,000.  In  a  similar  ^k 
manner,  turbidity  in  the   250   cubic     ^^$M^^M8^S4k§^^ 

centimeter  bottle  indicates  10  parts     [ "_ 

in    10,000  ;  in  the  300,   8  parts ;  in      '^'- 
the    350,  7  parts    and    in    the   400,  Fig.  23. 

less  than  6  parts.  The  ability  to  conduct  more  accurate  analyses 
can  only  be  attained  by  special  study  and  a  knowledge  of  chem- 
ical properties  and  methods  of  investigation. 

Air  Required  for  Ventilation.  The  amount  of  air  required 
to  maintain  the  standard  of  purity  can  be  very  easily  determined 
provided  we  know  the  amount  of  carbonic  acid  given  of¥  in  the 
process  of  respiration.  It  has  been  found  by  experiment  that  the 
average  production  of  carbonic  acid  by  an  adult  at  rest  is  about 
.6  cubic  feet  per  hour.  If  we  assume  the  proportion  of  this  gas 
as  4  parts  in  10,000  in  the  external  air,  and  are  to  allow  6  parts 
in  10,000  in  an  occupied  room,  the  gain  will  be  2  parts  in  10,000, 
or  in  other  words  there  will  be  yo",f o^o—  •0002  cubic  feet  of  car- 
bonic acid  mixed  with  each  cubic  foot  of  fresh  air  entering  the 
room. 

Therefore,  if  one  person  gives  off  .6  cubic  feet  of  carbonic 
acid  per  hour  it  will  require  .6  -f-  .0002  =  3000  cubic  feet  of  air 
per  person  to  keep  the  air  in  the  room  at  the  standard  of  purity 
assumed,  tliat  is,  6  parts  of  carbonic  acid  in  10,000  of  air. 


UK  \ri\(;  AND  \  I'.xrii.A'iMox 


The  follow  iiit4'  t;»l»l»'  lias  Iutu  (•oiiipiilfd  in  I liis  inaiiiicr  and 
slu»ws  till'  aiiioimt  ot'  air  wliicli  must  lie  iiit  lodiiccd  lor  caih  jicrsoii 
ill  ordrr  to  inaiiitaiii  \arii>iis  standards  ol'   pniity: 

TABLE  I. 


STANDARD  PARTS   OF 

I'AHBONIO  Al'II)  IN 

10.000  OK  AIK  IN 

ROOM. 


CUBIC  FEET  OK  Mil  HIUilMHKl)   I'lUl  PERSON. 
I'KR  .MINUTK.  I'liK  HOUK. 


8,0()0 

4,000 

2,GG7 
2,000 
1,000 
1,833 
1,151 
1,000 


Wliile  this  table  givi  s  tlic  theoretical  quantities  of  air 
required  for  different  .st;indaid.s  (d"  piii-ity,  and  may  lie  used  as  a 
j,aii(le,  it  will  be  better  in  aetual  practice  to  use  (piaiitities  w  liidi 
experience  has  shown  to  give  good  results  indifferent  t\i)(;s  of 
buildings.  Authorities  differ  somewhat  in  their  recomuiendations 
on  this  |)oint  and  the  pi-esent  tendency  is  toward  an  increase  of 
air. 

The  following  table  represents  good  modern  practice  and  may 
\x'  used  with  .satisfactory  results  : 

TABLE  II. 


Aia  SUPPLY  PER  OCCUPANT   FOR 

CUBIC  FEET 
PER  MINUTE. 

CUBIC  FEET 
PER  HOUR. 

Ho.s pi  tills 

50  to 

80 

8,000  to  4,800 

High  Schools 

50 

8,00) 

fi  ram  mar  Schools 

40 

2,400 

Theatres  and  Asseinlily  Halls 

25 

1,500 

Churches 

20 

1.-2()0 

Force  for  Moving  Air.      Air    is    mov(;d    for   ventilating    jmii'- 
jMises  in  two  ways;  first,  by  expansion  <liie  to  heating;  and  second 


HEATING  AND  VENTILATION. 


23 


by  mechanical  means.  The  effect  of  heat  on  the  air  is  to  increase 
its  vohime  and  therefore  lessen  its  density  or  weight,  so  that  it 
tends  to  rise  and  is  replaced  by  the  colder  air  below.  The  avail- 
able force  for  moving  air  obtained  in  this  way  is  very  small  and  is 
quite  likely  to  be  overcome  by  wind  or  external  causes.  It  will  be 
found  in  general  that  the  heat  used  for  producing  velocity  in  this 
manner,  when  transformed  into  work  in  the  steam  engine,  is 
greatly  in  excess  of  that  required  to  produce  the  same  eifect  by 
the  use  of  a  fan.  Ventilation  by  mechanical  means  is  performed 
either  by  pressure  or  suction.  The  former  is  used  for  delivering 
fresh  air  into  a  building  and  the 
latter  for  removing  the  foul  air 
from  it.  By  both  processes  the 
air  is  moved  without  change  in 
temperature,  and  the  force  for 
moving  must  be  sufficient  to 
overcome  the  effects  of  wind 
or  changes  in  outside  tempera- 
ture. Some  form  of  fan  is  used 
for  this  purpose. 

Measurements  of  Velocity. 
The  velocity  of  air  in  venti- 
lating ducts  and  flues  is  measured  directly  l)y  an  instrument  called 
an  anemometer.  A  common  form  of  this  instrument  is  shown  in 
Fio-.  24.  It  consists  of  a  series  of  flat  vanes  attached  to  an  axis, 
and  a  series  of  dials.  The  revolution  of  the  axis  causes  motion 
of  the  hands  in  proportion  to  the  velocity  of  the  air,  and  the 
result  can  be  read  directly  from  the  dials  for  any  given  period. 

AIR   DISTRIBUTION. 

The  location  of  the  air  inlet  to  a  room  depends  upon  the  size 
of  the  room  and  the  purpose  for  which  it  is  used.  In  the  case  of 
living  rooms  in  dwelling  houses,  the  registers  are  placed  either  in 
the  floor  or  in  the  wall  near  the  floor ;'  this  brings  the  warm  air  in 
at  the  coldest  part  of  the  room  and  gives  an  opportunity  for  warm- 
ing or  drying  the  feet  if  desired.  In  the  case  of  school  rooms 
where  large  volumes  of  warm  air  at  moderate  temperatures  are 
required,  it  is  best  to  discharge  it  through  openings  in  the  wall  at 


Fig.  24. 


•24 


111'  \  ri\";  WD  \'i:\rii,  A'nox. 


a  hfiirht  of  7  or  8  foot  t'lom  tin*  lloor  :  this  L;ivos  ;i  nioro  even  dis- 
trihiltion  as  tlu*  wanner  air  tends  to  rise  and  licnro  si)r('ads  nni- 
formlv  undiM-  the  ooilin!^  ;  it  then  L,Tadnally  displaces  other  air  ami 
the  nHim  beeoines  HUed  witli  pure  air  without  sensihU'  curi-ents  or 
ilmfts.  The  oooh-r  aii-  siidcs  to  the  bottom  of  the  romn  and  ean 
Ik^  taken  off  thnnig^h  ventihitinu^  rei^isters  phiced  near  the  floor. 
The  rehitive  positions  of  the  inlet  and  outlet  are  often  governed 
to  some  extent  by  tlie  building  eonstruction,  but  if  possible  they 
sluniM  both  be  loeated  in  tlie  same  side  of  the  room.  Figs.  2o, 
2«i  and  i!T  show  eonnnon  arrani^emeiits. 


CK/T3/D£    V^ALL 

Fiff.  25. 


OUTSIDE  WALL 
Fi.'.   2(5. 


outs/de:  v/all 
Fi<;-.  27. 


The  vent  outlet  .should  always  if  possi])le  be  placed  in  an 
inside  wall  else  it  will  become  chilled  and  the  air-How  through  it 
will  lx?come  sluggisli.  In  theatres  or  halls  which  are  closely 
packed,  the  air  should  enter  at,  or  near,  tlie  floor  in  finely-divided 
streams,  and  the  discharge  ventilation  should  be  through  openings 
in  the  ceiling.  The  reason  for  this  is  the  large  amount  of  animal 
heat  given  off  from  the  bodies  of  the  audience,  whicdi  causes  the 
air  to  l>ecoTne  still  further  lieated  after  entering  the  room,  and  the 
tendency  is  to  rise  continuously  from  floor  to  ceiling  thus  carrying 
away  all  impurities  from  respiration  as  fast  as  they  are  given  off. 

The  matter  of  air  velocities,  size  of  Hues,  etc.,  will  be  taken 
up  under  the  head  of  design. 

HEAT   LOSS  FROM  BUILDINGS. 

A  British  Thermal  Unit,  or  B.  T.  U.,  has  been  defined  as  the 
amount  of  heat  required  to  raise  the  temperature  of  one  pound  of 
water  one  degree  F.     Tliis  measure  of  heat  enters  into  many  of 


HEATING  AND  VENTILATION.  25 


the  calculations  involved  in  the  solving  of  problems  in  heating 
and  ventilation,  and  one  should  familiarize  himself  with  the  exact 
meaning  of  the  term. 

Causes  of  Heat  Loss.  The  heat  loss  from  a  building  is  due 
to  the  following  causes ;  first,  radiation  and  conduction  of  heat 
througli  Avails  and  windows  ;  second,  leakage  of  warm  air  around 
doors  and  windows  and  through  the  walls  themselves ;  and  thirds 
heat  ]"equired  to  warm  the  air  for  ventilation. 

Loss  Through  Walls  and  Windows.  The  loss  of  heat 
through  the  walls  of  a  building  depends  upon  tlie  material  used, 
the  thickness,  the  number  of  layers  and  the  difference  between 
the  inside  and  outside  temperatures.  The  exact  amount  of  heat 
lost  in  tliis  way  is  very  difficult  to  determine  theoretically,  hence 
we  depend  principally  on  the  results  of  experiments. 

Loss  by  Air  Leakage.  The  leakage  of  air  from  a  room  varies 
from  one  to  two  or  more  changes  of  the  entire  contents  per  hour, 
depending  upon  the  construction,  opening  of  doors,  etc.  It  is 
common  practice  to  allow  for  one  change  per  hour  in  well-con- 
structed buildings  where  two  walls  of  the  room  have  an  outside 
exposure.  As  the  amount  of  leakage  depends  upon  the  extent  of 
exposed  wall  and  window  surface  it  seems  best  to  allow  for  this 
loss  by  increasing  that  due  to  conduction  and  radiation.  Tlie 
following  table  gives  the  heat  losses  through  different  thickness  of 
walls,  doors,  windows,  etc.,  in  B.  T.  U.,  per  square  foot  of 
surface  per  hour  for  varyi)ig  differences  in  inside  and  outside 
temperatures. 

Authorities  differ  considerably  in  the  factors  given  for  heat 
losses,  and  there  are  various  methods  for  computing  the  same. 
The  following  figures  and -methods  have  baen  used  extensively  in 
actual  practice  and  have  been  found  to  give  good  results  when 
used  with  judgment. 


•2« 


llKAriNi.    AM)   \' i:\TiLATiO.N, 


TAIUJ:   III. 


Difference  between  inside  and  outside  temperatures. 


H»  Brick  Wall 
12'  Hriik  Wall 
H".'  Vnwk  Will 
2tt'  Hii.k  Wail 
•jr  Brltk  Wall 
•J>'   l$riik  Wall 
;5-J'   Hriik  Wall 
Siiij^'lf  Window 
Doiiltle  Window 
Sinf,'lr  Skvliuht 
Doiildf  Skvlifj;ht 
r  Woodrii  Door 
•J'  Woo(li-n  Door 
Comrrti'  Floor  on  lirirk  Arch 
Wood  Floi>r  on  IJrick  Arch 
Doiihlf  Wood  Floor 
Walls  of  Ordinary 
Wooden  Dwellings 


10° 

20° 

30° 

40° 

50° 

60° 

70° 

80° 

90° 

100° 

5 

9 

18 

18 

22 

27 

31 

36 

40 

45 

4 

7 

10 

13 

16 

20 

23 

26 

30 

33 

3 

5 

8 

10 

13 

16 

19 

22 

24 

27 

2.8 

4.5 

7 

9 

11 

14 

16 

18 

20 

23 

2.5 

4 

6 

8 

10 

12 

14 

16 

18 

20 

2 

3.5 

4.5 

7 

9 

11 

13 

14 

16 

18 

1.5 

3 

5 

6 

8 

10 

11 

13 

15 

16 

12 

24 

36 

49 

60 

73 

85 

93 

105 

8 

16 

24 

32 

40 

48 

56 

62 

70 

11 

21 

'31 

42 

52 

63 

73 

84 

94 

7 

14 

20 

28 

35 

42 

48 

56 

(i2 

4 

8 

12 

16 

20 

24 

28 

32 

3() 

40 

3 

5 

8 

11 

14 

17 

20 

23 

25 

28 

2 

4 

6.5 

9 

11 

13 

15 

18 

20 

22 

1.5 

3 

4.5 

6 

7 

9 

10 

12 

13 

15 

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

3 

5 

8 

10 

13 

16 

19 

22 

24 

27 

For  .solid  stone  walls  multiply  the  figures  for  Lrick  of  the  same 
thickness  by  1.7.  Where  rooms  have  a  cold  attic  above  or  cellar 
beneath,  multiply  the  heat  loss  through  walls  and  windows  by  1.1. 
The  figures  given  in  table  III.  are  for  a  southern  exposure  ;  for 
'other  exposures  multiply  the  heat  loss  given  in  table  III.  by  the 
factoiTs  given  in  tal)l('  IV. 

TABLE    IV. 


Exposure. 


Factor. 


N. 

1.32 

E. 

1.12 

S. 

1.0 

w. 

1.20 

N.  E. 

1.22 

N.  W. 

1.26 

S.  E. 

l.Of) 

s.  w. 

1.10 

N.  E.  S.  W.  or  total  exposure. 

i.k; 

In  order  to  make  the  use  of  the  table  clear  we  will  give  a 
number  of  examples  illustrating  its  use. 

Assuming  an  inside  temperature  of  70",  what  will  l)e  the 
heat  loss  from  a  room  liavingaii  exposed  wall  surface  of  200  square 


HEATING  AND  VENTILATION.  27 


feet  and  a  glass  surface  of  50  square  feet,  when  the  outside  tem- 
perature is  zero.  The  wall  is  of  brick,  16  inches  in  thickness  and 
has  a  southern  exposure;  the  windows  are  single. 

We  find  from  table  III.  that  the  factor  for  a  16"   brick  wall 
with  a  difference  in  temperature  of  70°  is  19,  and  that  for  glass 
(single  window)  under  the  same  condition  is  85  ;  therefore 
Loss  through  walls        =  200  X  19  =  3800 
Loss  through  windows  :=  50     X  85  =  4250 


Total  loss  per  hour  ^  8050  B.  T.  U. 

In  computing  the  heat  loss  through  walls,  only  those  exposed 
to  the  outside  air  are  considered. 

A  room  15  ft,  square  and  10  ft,  high  has  two  exposed  walls; 
one  toward  the  north  and  tlie  other  toward  the  east.  There  are 
4  windows,  each  3'  X  6'  in  size  The  two  in  the  north  wall  are 
double  while  the  other  two  are  single.  The  walls  are  of  brick,  20 
inches  in  thickness;  with  an  inside  temperature  of  70°  what  will 
be  the  heat  loss  per  hour  when  it  is  10°  below  zero. 

Total  surface        =  15  X  10  X  2  =  300 

Glass  surface        =     3x     6x4:=    72 

Net  wall  surface  =  228 

Difference  between  inside  and  outside  temperature  80°. 

Factor  for  20"  brick  wall  is  18. 

Factor  for  single  window  is  93, 

Factor  for  double  window  is  62, 

The  heat  losses  are  as  follows : 

Wall,  228  X  18  =  4104 

Single  windows,    36  X  93  =  3348 

Double  windows,   86  X  62  =  2232 


9684  B,  T,  U, 
As  one  side  is  toward  the  north  and  the  other  toward  the  west 
the  actual  exposure  is  N,  W,     Looking  in  table   IV,  we  find  the 
correction  factor  for  this  exposure  to  be  1.26  ;  therefore  the  total 
heat  loss  is 

9684  X  1,26  =  12,201,84  B,  T.  U. 
A  dwelling  house  of  wooden  construction  measures  IGO  ft. 


2S  III'.  \  i'l\t.     \\l>   \  I'.Xril.ATIDN. 

nixmiul    tlu'   oulsiilf;    it    has  -J   slurics,  carli    S    fl.    in    liciLclit  ;   tluf 

\viiul(»\vs    :uv    siiiirlt'    ami    tlir    i,^lass    siirracc    amounts    (o         the 

.) 

total    exiMisiuv  :   tho    altii-    and    ii'llar    arc     unwaiined.      If   8000 

1».  T.  r.  :iie  ulili/.t'd  from  iMch   iioiiml  of  coil  burned    in    tlio  fiir- 

iiaci'.  lu)\v  many  pounds  will   l»o  n'tjuircMl    per   hour  io  maintain  a 

icmi.fiaturi'  of  TO'  when  it  is  20°  ahove  /.ero  outside. 

Iota!  exposure  :=     10'>  X  tO  =  2560 

(i lass  surface     =  'i.HlO  ^    5=    512 


Net  wall  =  2048 

Temperature  dillerence  =:  70  —  20  =  50° 
Wall         2048  X  13      =  26024 
(ihiss  512  X  60      =  30720 


57;;44  B.  T.  U. 

As  the  buildiui,'  is  exposed  on  all  sides  the  factor  for  exposure 
will  \k'  the  average  of  those  for  N.  E.  S.  and  W.  or 
1 .32  -f  1 .12  +  1.0  +  1.20  ^  4  =  1.16 

The  house  Jias  a  cold  cellar  and  attic  so  we  must  increase  the 
heat  loss  10%  for  each  or  20^  for  both.  Making  these  correc- 
tions we  shall  have 

57344  X  1.1<»  X  1.20  =  79822  B.  T.  U. 

One  pound  of  coal  furnishes  8000  B.  T.  U.  then  79822  4- 
8000  =  9.97  ;  or  about  10  pounds  of  coal  per  hour  will  be  required 
to  warm  the  building  to  70°  under  the  conditions  stated. 

Approximate  Method.  For  dwelling  houses  of  usual  con- 
struction the  following  simple  method  may  be  used.  Multiply 
the  total  exposed  surface  by  38,  which  will  give  the  heat  loss  in 
li.  T.  U.  per  hour  for  an  inside  tempeiature  of  70°  in  zero  weather. 

This  factor  is  obtained  in  the  following  manner.     Assume 

the  gUss  surface  to  be   -  the  total  exposure,  which  is  an  average 

proi>ortion. 

Then  e;u;h  square  foot  of  exposed  surface  consists  of  _  glass 

and  '1  wall  and  the  heat  loss  for  70'^  dilfercnce  in   temperature 
6 

wouI«l  1)6  as  follows  : 


HEATING  AND  VENTILATION.  29 

Wall    i^  X  19  =r  15.8 

6 

Glass    1  X  85  =  1^ 
6  29.9 

Increasing  this  by  16%  for  total  exposure  and  10%  for  loss 
through  ceilings  we  have  29.9  X  l.K:!  X  1-10  =  38.1.  The  loss 
through  floors  is  considered  as  being  offset  by  including  the 
kitchen  walls  of  a  dwelling  house,  which  are  warmed  by  the 
range  and  would  not  otherwise  be  included  if  computing  the  size 
of  a  furnace  or  boiler  for  heating. 

If  the  heat  loss  is  required  for  outside  temperatures  other 
tlian  zero,  corrections  must  be  made  as  follows :  Multiply  by  50 
for  20°  below  zero,  by  41  for  10°  below,  by  33  for  10°  above. 

This  method  is  convenient  for  approximations  in  the  case  of 
dwelling  houses  but  the  more  exact  method  should  be  used  for 
other  types  of  buildings,  and  in  all  cases  for  computing  the  heat- 
ing surface  for  separate  rooms.  When  calculating  the  heat  loss 
from  isolated  rooms,  the  cold  inside  walls  as  well  as  the  outside 
must  be  considered. 

The  loss  through  a  wall  next  to  a  cold  attic  or  other  un- 
warmed  space  may  in  general  ]:»e  taken  as  about  two-thirds  that  of 
an  outside  wall. 

Heat  Loss  by  Ventilation.  One  B.  T.  U.  will  raise  the 
temperature  of  1  cubic  foot  of  air  55  degrees  at  average  temper- 
atures and  pressures  or  will  raise  55  cubic  feet  1  degree,  so  that 
the  heat  required  for  the  ventilation  of  any  room  ma}'"  be  found 
by  the  following  formula : 

cu.  ft.  of  air  per  hour  X  number  of  degrees  rise  _  ]j   T   U   reouired 
55 

To  compute  the  heat  loss  for  any  given  I'oom  Avliicli  is  to  be 
ventilated,  first  find  the  loss  through  walls  and  windows,  and 
correct  for  exposure,  then  compute  the  amount  required  for 
ventilation  as  above  and  take  the  sum  of  the  two.  An  inside 
temperature  of  70°  is  always  assumed  unless  otherwise  stated. 

Example  —  Wliat  quantity  of  heat  will  be  re(iuii-ed  to  warm 
100,000  cubic  feet  of  air  to  70°  for  ventilating  purposes  when  the 
outside  temperature  is  10  below  zero? 

100,000  X  80  ~  55  =  145,454  B.  T.  U.     Ans. 


30  IlKATINt;   AND   \  KNTI  I.ATIOX. 


How  many  l».  I".  I  .  will  Ik'  iH'([nirt'tl  |>cr  hour  lor  llu;  vriiti- 
hitioM  of  a   (.Imii'li  sfatiiii;  500    |>t'0[il(>,   in    /cro  wcallicr? 

lu'tVrrinu^  to  tablf  II.  we  liiul  that  tlu-  total  air  i(>(iiiiro<I  per 
hour  is  1200  X  ■'>'>0  —  OOO.OOO  en.  ft.:  th.Mvf.Mv  (;00,0()0  X  70  -^ 
5r>  =  708,G3(>  \\.  r.  V . 

EXAMPLES  FOR  PRACTICE. 

1.  A  room  ill  a  i^rainiuar  school  28' X  82' and  12'  hi^-h  is 
to  acoommoilate  oO  pajjils.  The  walls  are  of  brick  10"  iix  thick- 
ness and  there  are  6  single  windows  in  the  room,  each  3'  X  ^'>'; 
theiv  are  warm  rooms  above  and  below;  the  exposure  is  S.  E 
How  many  B.  T.  V.  will  bo  required  per  hour  for  warming  the 
room  and  how  many  ft)r  ventilation,  in  z(M"o  weatlier? 

Ans.      22,0")t)  -|-  for  warming,  152,727  -\-  for  ventilation. 

2.  A  stone  church  seating  400  people  has  walls  20"  in 
thickness.  It  has  a  wall  exposure  of  5,000  square  feet,  a  glass 
«*xposure  (single  windows)  of  GOO  square  feet,  and  a  roof  ex- 
posure of  7,000  square  feet ;  the  roof  is  of  2"  pine  plank  and  the 
factor  for  lieat  loss  may  be  taken  the  same  as  for  a  2"  wooden  door. 
The  floor  is  of  wood  on  l)rick  arches  and  has  an  area  of  4,000 
square  feet.  The  building  is  exposed  on  all  sides.  What  will 
be  the  heat  required  per  hour  for  both  warming  and  ventilation 
when  the  outside  temperature  Ls  20°  above  zero  ? 

Ans.  296,380  for  warming  ;  430,363  -|-  foi'  ventilation. 

3.  A  dwelling  house  of  wooden  construction  measures  200 
feet  around  the  outside  and  hfus  3  stories,  each  9  feet  high :  com- 
pute the  heat  loss  1)y  the  appnjximato  metliod  when  the  temper- 
ature is  20°  below  7,ero. 

Ans.     270,000  li.  T.  U.  per  hour. 

FURNACE    HEATING. 

Types  of  Furnaces.  Furnaces  may  l)e  divided  into  two 
general  types  known  as  direct  and  indirect  diaft.  Fig.  28  shows 
a  conamon  foi-m  of  direct  draft  fuinace  with  a  brick  setting;  the 
Ijetter  cla.ss  have  a  radiatoi',  generally  placed  at  the  top,  through 
which  the  ga.se8  pass  before  reaching  the  smoke  pipe.  The}^  have 
but  one  damper  usually  coml)ined  with  a  cold-air  check.  jNIany 
of  tlie  c:hea|)er  direct  draft  furnaces   hav(»  no  radiator   at  all ;  the 


HEATING  AND  VENTILATION. 


31 


gases  passing  directly  into  the  smoke  pipe  and  carrying  away  much 
heat  that  should  be  utilized. 

The  furnace  shown  in  Fig.  28  is  made  of  cast  iron  and  has 
a  large  radiator  at  the  top  ;  the  smoke  connection  is  shown  ?.t  the 
rear. 

Fig.  29  represents  another  form  of  direct  draft  furnace.  In 
this  case  the  radiator  is  made  of  sheet  steel  plates  riveted  together, 


Fig.  28. 

and  the  outer  casing  Is  of  heavy  galvanized  iron  instead  of  brick. 
In  the  ordinary  indirect  draft  type  of  furnace  (see  Fig.  30) 
the  gases  pass  downward  through  flues,  to  a  radiator  located  near 
the  base,  thence  upward,  through  another  flue  to  the  smoke  pipe. 
In  addition  to  the  damper  in  the  smoke  pipe,a  direct  draft  damper 
is  required  to  give  direct  connection  with  the  funnel  when  coal  is 
first  put  on,  to  f?i.cilitate  the  escape  of  gas  to  the  chimney.      When 


ai» 


hi: A'n\<;  a\i>  NKX'ni.A'riox, 


llu'  (  liiiuiirv  tliatl  is  \\i';ik,  liduMi'  finm  l>;hs  is  iiHiif  likclv  to  lie 
t'XjH'rii'urrtl  wiili  fiiniaccs  of  this  lypt'  tliiiii  wilii  those  h;iviiiL;- u 
(iiivct  (Irat'l. 

Qrates.  Ni>  part  of  a  tiinun'c  is  of  moi't'  importance  than  the 
I'rutos.  1  '>•'  I'hiiii  ignite  rotatinijiibdut  a  center  pin  \\as  for  a  lon^ 
lime   the  one   most  commonly    used.      These  grates   were   usually 


Fip.  20. 


provided  witli  a  clinker  door  for  removin((  uny  i-efuse  too  large  to 
j)asH  between  the  grat<i  bars.  The  action  of  sucli  gi-ates  tends  to 
leave  a  cone  of  aslies  in  the  center  of  the  fire  causing  it  to  burn 
more  freely  around  the  edges.  A  better  foim  of  grate  is  the 
revolving  triangidar  pattern  wliich  is  now  used  in  jnaiiy  of  the  lead- 


HEATING  AND  VENTILATION. 


38 


ing  furnaces.  It  consists  of  a  series  of  triangular  Ijars  having 
teeth.  The  bars  are  connected  by  gears  and  are  turned  by  means 
of  a  detacliable  lever.  If  properly  used  this  grate  will  cut  a  slice 
of  ashes  and  clinkers  from  under  the  entire  fire  with  little,  if  any 
loss  of  unconsumed  coal. 

The  Fire  Pot.      Fire  pots  are  generally  made  of  cast  iron  or 
of  steel  plate  lined  with  fire  bi'ick.      The  depth  ranges  from  about 


Fig.  30. 


12  to  18  inches.  In  cast  iron  furnaces  of  the  better  class  the  fire 
pot  is  made  very  heavy  to  insure  durability  aiul  to  render  it  less 
likely  to  become  red  hot.  The  fire  pot  is  sometimes  made  in  two 
pieces  to  reduce  the  liability  of  cracking.  The  heating  surface 
is  sometimes  increased  by  corrugations,  pins  or  ribs. 

A  fire  brick  lining  is  necessary  in  a  wrought  iron   or  steel 
furnace  to  protect  the  thin  shell   from  the  intense  heat  of  the  fire. 


34  lIKAriNt;    AM)   V  KN  IM  l-A  TIOX. 


Siiu-t*  lirii'k  lincil  lin-  pols  art-  imu'li  less  ('(Tcctivc  tli;iii  cast,  iron 
in  tr.uisinittiiiLT 'it'iit.  such  furnaces  depi'iul  to  a  uroat,  extent  for 
their  etlieieiu'v  on  tlu'  IieatinLj  sni'faee  in  tlie  donui  and  ladiator, 
and  this  as  a  rule  is  niiieh  lT''*'  il<'r  than  in  tliose  ot   east  iron. 

Cast  iron  furnnees  have  th«^  iidvantai^e  when  coal  is  first  pnt 
on,  (and  the  drop  tines  and  radiator  are  cnt  out  by  the  dircujt 
damper")  of  still  «j^ivin<if  olT  heat  from  the  fii-e  j)ot,  while  in  the  case 
«>f  hriek  linings  very  little  heal  is  given  oil"  in  this  way  and  the 
rooms  are  likely  to  become  somewhat  cooled  before  the  fresh  coal 
bce.Mnes  thoroughly  ignited. 

Combustion  Chamber.  T\n\  body  of  the  furnace  above  the 
liie  pot,  commonly  called  the  dome  or  feed  section,  provides 
a  combnstion  chamber.  This  chamber  should  be  of  sufficient 
size  to  permit  the  gases  to  become  thoroughly  mixed  with  the  i'.ir 
j)assing  up  through  the  tire  or  entering  through  openings  provided 
for  the  purpose  in  the  feed  door.  In  a  well-designed  furnace  this 
s[taee  should  be  somewhat  larger  than  the  lire  pot. 

Radiator.  The  radiator,  so  called,  with  which  all  furnaces 
of  the  better  class  are  provided,  acts  as  a  sort  of  reservoir  in 
which  the  gases  are  kept  in  contact  with  the  air  passing  over  the 
furnace  until  they  have  parted  with  a  considerable  portion  of 
tln'ir  heat.  Kadiators  are  built  of  cast  iron,  of  steel  plate  or  of 
a  combination  of  the  two.  The  former  is  more  duiable  and  can 
Ije  made  with  fewer  joints,  but  owing  to  the  difficulty  of  casting 
radiators  of  large  size,  steel  plate  is  commonly  used  for  the  sides. 

The  effectiveness  of  a  radiator  depends  on  its  form,  its  heat- 
ing surface  and  the  difference  between  the  temperature  of  the 
g:ises  and  the  surrounding  air.  Owing  to  the  accunndation  of 
BfK)t,  the  lM)ttom  surface  becomes  practically  worthless  after  the 
fuinaee  has  l>een  in  use  a  short  time  ;  surfaces  to  be  effe(;tive 
must  therefore  be  self-cleaning. 

If  the  radiator  is  placed  near  the  bottom  of  the  fuinace  the 
ga.ses  are  Hurrounded  l)y  air  at  tlie  lowest  temperature,  which 
rcniders  the  radiator  more  effective  for  a  given  size  than  if  placed 
near  the  top  and  surrounded  by  warm  air.  On  the  other  hand, 
the  cold  air  lias  a  tendency  U)  condense  the  gases,  and  the  acids 
thus  formed  are  likely  to  corrodf*  the  iron. 

Heatinjf  Surface.     Tlie  diffcrciit    heating   surfaces  may  be 


iip:ating  and  ventilation. 


described  as  follows  :  Fire  pot  surface  ;  surfaces  acted  upon  by 
direct  lays  of  heat  from  the  fire,  such  as  the  dome  or  combustion 
chamber;  gas  or  smoke  heated  surfaces,  such  as  flues  or  radiators 
and  extended  surfaces,  such  as  pins  or  ribs.  Surfaces  unlike  in 
character  and  location,  vary  greatly  in  heating  power,  so  that  in 
making  comparisons  of  different  furnaces  we  must  know  the  kind, 
form  and  location  of  the  heating  surfaces  as  well  as  the  area. 

In  some  furnaces  having  an  unusually  large  amount  of  sur- 
face, it  will  be  found  on  inspection  that  a  large  part  would  soon 
become  practically  useless  fri)m  the  accumulation  of  soot.  In 
others  a  larje  portioi  of  the  surface  is  lined  with  fire  brick,  or  is 
so  situated  that  the  air  currents  are  not  likely  to  strike  it. 

The  ratio  of  grate  to  heating  surface  varies  somewhat  accord- 
ing to  the  size  of  furnace.  It  miy  be  taken  as  varying  from  1  to 
2.5  in  the  smaller  sizes  and  1  to  1.5  in  the  laro^er. 

Efficiency.  One  of  the  first  items  to  be  determined  in  esti- 
mating the  heating  capacity  of  a  furnace  is  its  efficiency,  that  is,  the 
proportion  of  the  heat  in  the  coal  that  may  be  utilized  for  warming. 
The  efficiency  depends  chiefly  on  the  area  of  the  heating  surface 
as  compared  with  the  grate,  on  Its  character  and  arrangement,  and 
on  the  rate  of  combustion.  The  usual  proportions  between  grate 
and  heating  surface  have  bsen  stated.  The  rate  of  combustion 
required  to  maintain  a  temperature  of  70°  in  the  house  depends 
of  course  on  the  outside  temperature.  In  very  cold  weather  a 
rate  of  4  to  5  pounds  of  coal  per  square  foot  of  grate  per  hour 
must  be  maintained. 

One  pound  of  good  anthracite  coal  will  give  off  about  13000 
B.  T.  U.  and  a  good  furnace  should  utilize  70  percent,  of  this  heat. 
The  efficiency  of  an  ordinary  furnace  is  often  much  less,  some- 
times as  low  as  50  per  cent. 

In  estimating  the  required  size  of  a  first-class  furnace  with 
good  chinniey  draft  we  may  safely  count  upon  a  maximum  com- 
bustion of  5  pounds  of  coal  per  square  foot  of  grate  per  hour,  and 
may  assume  that  8000  B.  T.  U.  will  be  utilized  for  warming  pur- 
poses from  each  pound  burned.  This  quantity  corresponds  to  an 
efficiency  of  GO  j)er  cent. 

Heating  Capacity.  Having  determined  the  heat  loss  from  a 
building  by  the  methods  given,  it  is    a  simple  matter   to    compute 


ao 


lIKATINMi    ANI>   \i:\"ni. A'IM()^^ 


the  sizt»  of  i^iMtt'   iu'i'ess:ii\-  ti»    Imrii   a   siil"licu'iit,  (luanlity  of  cojil 
to  fiiniisli  tlu'  iiniiMiiit  of   heat  it'iniircd  for  w  ariiiiiiL;'. 

As:i  mutter  of  illiistrat ion  we  iiia\ consider  llic  licat  (Udivored 
{o  iho  rooms  as  inadt*  up  of  two  parts;  lirst,  that  riMiiiircd  to  warm 
tlio  outsido  air  up  to  70'^  (^tlie  tomperature  of  the  rooms)  and 
second,  tlie  ijnantitv  wliiidi  uuisl  he  adiled  to  this  to  ol'fset  tlu;  loss 
tiuouirh  walls  aud  wiiulows.  Air  is  usually  delivered  at  the 
rejjistoi's  at  about  140  derives  under  zero  conditions  outside;  this 
air  leaves  tlie  rooms  hy  leakafre  at  a  temperature  of  70  degrees,  (the 
normal  inside  temperature)  having  lost  one-half  its  heat  by  con- 
duetion,  radiation,  etc.,  so  that  the  heat  given  to  the  entering  air 
must  l>e  twice  that  Avhieh  we  have  computed  for  loss  through 
walls,  etc. 

Example.  —  The  loss  through  the  walls  and  windows  of  a 
building  is  found  to  be  80000  B.  T.  U.  per  hour  in  zero  weather, 
what  will  be  the  size  of  furnace  required  to  maintain  an  inside 
temperature  of  70  degrees? 

From  the  above  we  have  the  total  heat  required,  equal  to 
80000  X  2  =  100000  B.  T.  U.  per  hour.  If  we  assume  that  8000 
W.  'W  V.  are  utilized  per  pound  of  coal,  then  160000  ^  8000  =  20 
[Hjunds  of  coal  required  per  hour,  and  if  5  pounds  can  be  burned 
on  each  stjuare  foot  of  grate  per  hour,  then  "^-^  ■=.  4  scjuare  feet 
required.  A  fire  pot  28  inches  in  diameter  has  an  area  of  4.27 
square  feet  and  is  the  size  we  should  use. 

The  following  table  will  be  found  useful  in  determining  the 
diameter  of  lire  pot  required: 

TABLE  V. 


AVERAOE  rJlAMETEE  OF  FIRE  POT 
IN  INCHES. 

AREA  IN  SQUARE  FEET. 

18 

1.77' 

20 

2.18 

22 

2.64 

24 

3.14 

20 

3.G9 

28 

4.27 

30 

4.91 

i]2 

5.68 

HEATING  AND  VENTILATION.  37 


If  the  outside  temperature  is  below  zero  the  method  of  com- 
putation becomes  slightly  different.  We  have  seen  that  in  zero 
weather  a  certain  quantity  of  heat  is  required  to  raise  the  temper- 
ature of  tlie  entering  air  from  zero  to  70°,  the  temperature  of  the 
room,  and  that  a  second  quantity  must  then  be  added  to  raise  the 
temperature  of  the  air  to  140  °,  which  is  the  usual  temperature 
of  delivery  at  the  registers.  This  last  quantity  is  to  offset  that 
lost  by  radiation  and  conduction,  and  must  equal  the  heat  loss 
from  the  building  as  computed  by  the  factors  given  in  tables  III. 
and  IV.  The  air  has  been  raised  through  140  degrees  and  ^{^ 
of  the  heat  suppUed  has  been  used  to  raise  it  to  the  temperature 
of  the  room  and  has  been  lost  by  leakage  ;  while  the  remaining 
70-,  an  equal  amount,  has  been  given  up  by  radiation  and  con- 
duction. In  this  case  we  have  only  to  compute  the  heat  loss  for 
radiation  and  conduction  by  the  rules  given  and  multiply  this 
result  by  2  to  obtain  the  total  amount  of  heat  to  be  supplied  by 
the  furnace. 

Now  take  a  case  where  it  is  10  degrees  below  zero.  If  the  air 
is  delivered  to  the  rooms  at  140  degrees  as  before,  it  must  be 
warmed  through  150  degrees.  Of  the  heat  supplied  j%\  has  been 
used  to  raise  the  temperature  of  the  outside  air  to  that  of  the 
room,  and  only  ^^^  for  loss  by  radiation  and  conduction.  As  in 
the  preceding  example,  this  latter  quantity  must  equal  the  com- 
puted heat  loss  through  walls  and  windows  ;  and  as  it  is  only 
-tJL  or  .466  of  the  total  amount  of  heat  required  we  must  mul- 
tiply it  by  1  ~  .466  =  2.14  instead  of  by  2  as  in  the  first  case 
where  the  outside  temperature  is  zero. 

In  the  same  manner  multiply  by  2.28  for  20  degrees  belo.w 
zero  and  by  2.42  for  30  degrees. 

EXAMPLES  FOR  PRACTICE. 

1.  A  brick  apartment  house  is  20  feet  wide,  and  has  4 
stories,  each  being  10  feet  in  height.  The  house  is  one  of  a  block 
and  is  exposed  only  at  the  front  and  rear.  The  walls  are  16 
inches  thick  and  the  block  is  so  sheltered  that  no  correction  need 
be  made  for  exposure.  Single  windows  make  up  L  the  total 
exposed  surface.  Figure  for  cold  attic  but  warm  basement. 
What  area  of  grate  surface  will  be  re(iuired  for  a  furnace  to  keep 


38  III:  VriNC     \M)    \  KX'I'II. ATIOX 


the    house  ;ii    ,i   t«'miM»mtiiiv  of    70"*  wlicii    it    is  10°   bellow  zero 
'»»tsi(h»:'  Alls.     ::.!)  s(|iiai(>  ft-ct. 

'J.  A  lioiist'  li;i\in^  ;i  fiiniiiiT  with  a  Ijic  |,(i(  :;()  indios  in 
(liuiMfitT  is  not  sunicifiitly  Wiuiiu'il  and  it  is  decided  to  add  a 
seeoiid  funiaee  to  he  used  in  eoiiiieetioii  with  tlie  one  ulieady  in. 
The  heat  h)>s  frniu  the  hiiiKhtejf  is  found  h\-  conipntation  to  he 
l:>:>,t»Oi)  H.  T.  V.  per  honr,  in  zero  weather.  What  diameter  of  lire* 
ix>t  will  he  re«inired  for  the  extra  fnrnaee? 

Ans.  18  inches. 
Location  of  Furnace.  A  fninace  shonhl  he  so  j)hiced  that 
tiie  warm-air  pipes  will  he  of  nearly  the  same  length.  The  air 
travels  most  leadily  thron;_,di  pipes  leadini;-  towaid  the  sheltered 
side  ot  the  lu)nse  and  to  tlu^  npper  rooms.  Therefore  pipes 
leading  Uiward  the  north  or  west  or  to  rooms  on  the  first  floor 
sliould  be  favored  in  regard  to  length  and  size.  The  fnrnaee 
should  be  placed  somewhat  to  the  north  or  west  of  the  center  of 
the  house  or  toward  the  points  of  compass  from  which  the  pre- 
vailing winds   blow. 

Smoke  Pipes.  Furnace  smoke  pipes  range  in  size  from 
ahont  •')  inches  in  the  smaller  sizes  to  8  or  9  inches  in  the  lai-ger 
ones.  They  are  generally  made  of  galvanized  iron  of  No.  24 
gjiuge  or  heavier.  The  pipe  should  be  carried  to  the  chimney  as 
directly  as  possible,  avoiding  bends  which  increase  the  resistance 
and  diminish  the  draft.  Where  a  smoke  pipe  passes  through  a 
partition  it  should  be  protected  by  a  soapstone  or  double  perfor- 
ated metal  collar  having  a  diameter  at  least  8  inches  greater  than 
that  of  the  pipe.  The  top  of  the  smoke  pipe  sliould  not  be  placed 
within  8  inches  of  unprotected  beams  nor  less  than  G  inches  under 
Ijeams  protected  by  asbestos  or  plaster  with  a  metal  shield  beneath. 
A  collar  to  make  tight  connection  with  the  (diinuiey  should  be 
riveted  to  the  pipe  about  ',  inches  finm  the  end  to  prevent  its 
\ni\ug  pushed  too  far  into  the  flue.  Where  the  pipe  is  of  unusual 
length  it  is  well  to  cover  it  to  prevent  loss  of  heat  and  the  con- 
densation of  smoke. 

Chimney  Flues.  ( 'himney  lines  if  built  of  brick  shouM  have 
walls  H  inch.'s  in  thickness,  uidess  terra  cotti  linings  are  use<l, 
when  only  4  inches  of  brick  work  is  required.  Excejit  in  small 
houses  where  an  8  X  8  Hue  may  be  used,  the  nominal  size  of  the 


HEATING  AND  VENTILATION.  39 

smoke 'flue  should  be  at  least  8  X  12  to  allow  for  contractions  or 
offsets.  A  clean-out  door  should  be  placed  at  the  bottom  of  the 
flue  for  removing  ashes  and  soot.  A  square  flue  cannot  be 
reckoned  at  its  full  area  as  the  corners  are  of  little  value.  To 
avoid  down  drafts  the  top  of  the  chimney  must  be  carried  above 
the  highest  point  of  the  roof  unless  provided  with  a  suitable  hood 
or  top. 

Cold=Air  Box.  The  cold-air  box  should  be  large  enough  to 
supply  a  volume  of  air  suflicient  to  fill  all  the  hot-air  pipes  at  the 
same  time.  If  the  supply  is  too  small,  the  distribution  is  sure  to 
be  unequal  arid  the  cellar  will  become  overheated  from  lack  of  air 
to  carry  away  the  heat  generated. 

If  a  box  is  made  too  small  or  is  throttled  down  so  that  the 
volume  of  air  entering  the  furnace  is  not  large  enough  to  fill  all 
the  pipes  it  will  be  found  that  those  leading  to  the  less  exposed 
side  of  the  house  or  to  the  upper  rooms  will  take  the  entire  supply, 
and  that  additional  air  to  supply  the  deficiency  will  be  drawn 
down  through  registers  in  rooms  less  favorably  situated.  It  is 
common  [)ractice  to  make  the  area  of  the  cold-air  box  three-fourths 
the  combined  area  of  the  hot-air  pipes.  The  inlet  should  be 
placed  where  the  prevailing  cold  winds  will  blow  into  it  ;  this  is 
commonly  on  the  north  or  west  side  of  the  house.  If  it  is  placed 
on  the  side  away  from  the  wind,  warm  air  from  the  furnace  is 
likely  to  be  drawn  out  through  the  cold-air  box. 

Whatever  may  be  the  location  of  the  entrance  to  the  cold-air 
box,  changes  in  the  direction  of  the  wind  may  take  place  which 
will  bring  the  inlet  on  the  wrong  side  of  the  house.  To  prevent 
the  possibility  of  such  changes  affecting  the  action  of  the  furnace 
the  cold-air  box  is  sometimes  extended  through  the  house  and  left 
open  at  both  ends,  with  check-dampers  arranged  to  prevent  back 
drafts.  These  checks  should  be  placed  some  distance  from  the 
entrance  to  prevent  their  becoming  clogged  with  show  or  sleet. 
The  cold-air  box  is  generally  made  of  matched  boards,  but  gal- 
vanized iron  is  much  better ;  it  costs  more  than  wood  but  is  well 
worth  the  extra  expense  on  account  of  tightness  which  keeps  the 
dust  and  ashes  from  being  drawn  into  the  furnace  casing  to  be 
discharged  through  the  registers  into  the  rooms  above. 

The  cold-air  inlet  should  be  covered  with  galvanized  wire 


40 


IIKAI'INC    AND   VKN  Til. A'IMOX 


QOLDAIFi 
/NLET  ■ 


A/£  TTir-JC. 


lU'ttiiii;  with  ;i  nu'sli  nf  ;it  least  tlircc-oitrlitlis  of  an  iiicli.  The 
frame  In  whii'h  it  is  aUarlu'd  should  not  hi-  sinallrr  than  the  iiisido 
dimensions  oi"  tlu*  cold-air  hox.  A  door  li>  a(huit  air  from  tlie 
cellar  to  tlu'  I'old-air  hox  is  LTcnorally  provided.  As  a  rule  air 
should  he  taken  from  this  soun-e  only  when  the  house  is  tcm- 
j>onirilv  nnoeeu|tiod  or  duiintj^  hic^h  winds. 

Return  Duct.  In  some  eases  it  is  desirahle  to  reluiii  air  to 
the  furnaee  from  the  rooms  above,  to  be  reheated.  Duets  for  this 
purpose  are  eommon  in  places  where  the  winter  tem[)erature  is 
FX)P  RETURNING  frequently    below    zero. 

T  Return  ducts  when  used, 

should  be  in  addition  to 
the  regular  cold-air  box. 
Fig.  81  shows  a  eom- 
mon method  of  making 
the  connection  between 
the  two.  By  proper 
adjustment  of  tlie  swing- 
ing damper  the  air  can 
b(!  taken  either  from  out 
of  doors  or  thi'ough  the 
register  from  the  room 
above.  The  return 
register  is  often  [)laced 
in  thf  hallway  of  a  house  so  that  it  will  take  the  cold  air  which 
rushes  in  when  the  door  is  openiid  and  also  that  which  may  h;ak 
in  around  it  while  closed.  Check  valves  or  flaps  of  light  gossa- 
mer or  woolen  cloth  should  be  placed  between  the  cold-air  box 
and  the  registers  to  prevent  back  drafts  during  winds. 

The  retuin  duct  should  not  be  used  too  freely  at  the  expense 
of  outdoor  air,  and  its  use  is  not  recommended  exce{)t  during  the 
nig])t  wIm'U  air  is  admitted  to  the  sleeping  rooms  through  open 
windows. 

Warm-Air  I^ipes.  Tlic  riMjuired  size  of  the  wai-ni-aii-  J)ij»e  to 
any  given  room  depends  upon  the  heat  loss  from  the  room  and  the 
volume  of  waiwn  air  required  to  offset  this  lo.ss.  Each  cul)ic  foot 
of  air  warmed  from  zero  to  140  degrees  brings  into  a  room  2.2 
13.  T.  U.     We  have  already  seen  that  in  zero  weather  with  the  air 


Fi-.  31. 


HEATING  AND  VENTILATION. 


41 


entering-  the  registers  at  140  degrees,  only  one-half  of  the  heat 
contained  in  the  air  is  available  for  offsetting  the  losses  by  radia- 
tion and  conduction,  so  that  only  1.1  B.  T.  U.  in  each  cubic  foot 
of  entering  air,  can  be  utilized  for  warming  purposes.  Therefore 
if  we  divide  the  computed  heat  loss  in  B.  T.  U.  from  a  room,  by 
1.1  it  will  give  the  number  of  cubic  feet  of  air  at  140  degrees 
necessary  to  warm  the  room  in  zero  weather. 

As  the  outside  temperature  becomes  colder  the  quantity  of 
heat  brought  in  per  cubic  foot  of  air  increases,  but  the  proportion 
available  for  warming  purposes  becomes  less  at  nearly  the  same 
rate,  so  that  for  all  practical  purposes  we  may  use  the  figure  1.1 
for  all  usual  conditions.  In  calculating  the  size  of  pipe  required, 
we  ma}'-  assume  maximum  velocities  of  280  and  400  feet  per 
minute  for  rooms  on  the  first  and  second  floors  respectively. 
Knowing  the  number  of  cubic  feet  of  air  per  minute  to  be  delivered, 
we  can  divide  it  by  the  velocity,  which  will  give  us  the  required 
area  of  the  pipe  in  square  feet. 

Round  pipes  of  tin  or  galvanized  iron  are  used  for  this  pur- 
pose. The  following  table  will  be  found  useful  in  determining 
the  required  diameters  of  pipe  in  inches. 

TABLE  VI. 


DIA.  OF  PIPE  IN  INCHES. 

AREA  IN  SQ.  INCHES. 

AREA  IN  SQUARE  FEET. 

6 

28 

.196 

7 

38 

.267 

8 

50 

.349 

9 

64 

.442 

10 

79 

.545 

11 

95 

.660 

12 

113 

.785 

13 

133 

.922 

14 

154 

1.07 

15 

177 

1.23 

16 

201 

1.40 

Example.  — The  heat  loss  from  a  room  on  the  second  floor  is 
22,000  B.  T.  U.,  per  hour.  Wliat  diameter  of  warm  ail-  pipe  will 
be  required? 


»J 


Ill.AIMNC    AND   NKNTII. ATIOX. 


•J-_\(K>0  -^  1.1  :  :  -JOjtOt)  -=  .Millie  irv{  of  :iir  iv.iiiiiv<l  [n-y  hour. 
•Jo.UOO  :-  i;0  -  ;]:]:)  per  iniimtt'.  Assiiiniiii^'  a  velocitvof  K)0  fcut 
ja'i-  inimito  we  hiivo  '>;^;5  -f-  H)0  —  .S.V2  s(|niin>  fcol,  wliicli  is  the 
aiva  of  |)i|u'  reijuired.  Ivcffiriiii,^  to  tuhh'  Vl.  we  liiid  this  conifis 
iM'tweeii  a  \-  and  l-">-iiuh  [»i|>»'  aiul  (he  hirgcr  size  would    |ndhahly 

Ih'    I'llOSfU. 

EXAflPLES    FOR    PRACTICE. 

1.  A  fust  lloor  room  luus  a  coniputed  loss  of  3;iOUU  li.  T.  U. 
per  hour  wheu  it  is  1<)^  heh)w  zero.  The  air  for  warming  is  to 
ent«M-  throui:;h  two  pipes  of  equal  size,  and  at  a  teuiperature  of  140 
deiijrees.      What  will  he  the  required  diameter  of  the  pipes? 

A  us.  13  inches. 
-.      It"    in    the  above    example    the    room    liad    becui   on    the 
seeond    lloor  and    the  air  was  to  he  delivered  through  a   single 
pipe;   what  diameter  would  be  required? 

Aus.  15  inches. 


Fit'.  32 


Fiff.  m. 


Since  long  horizontal  runs  of  pipe  increase  the  resistance  and 
loss  of  heat,  they  should  not  in  general  be  over  15  feet  in  length. 
This  applies  especially  to  pipes  leading  to  rooms  on  the  first  floor 
or  t^)  those  on  the  cold  side  of  tlie  house.  Pipes  of  excessive 
length  should  be  inci-eased  in  size  because  of  the  added  resistance. 

Figs.  32  and  33  sliow  coiuiuou  uiethods  of  lunning  tin;  pipes 
in  the  ba.sement.  The  first  gives  the  best  results  and  should  be 
used  where  the  Ijasement  is  of  sufficient  height  to  allow  it.  A 
damper  should  1)e  placed  in  each  j)ipe  near  the  furnace  for  regulat- 
ing the  flow  of  air  to  the  difTerent  looms  or  for  shutting  them  off 
entirely  when  desired. 


HEATING  AND  VENTILATION. 


43 


While  round  pipe  risers  give  the  best  results,  it  is  not  always 
j)ossible  to  provide  a  sufficient  space  for  them,  and  flat  or  oval  pipes 
are  substituted.  When  vertical  pipes  must  be  placed  in  single 
partitions,  nuich  better  results  will  be  obtained  if  the  studding 
can  be  made  5  or  6  inches  deep  instead  of  4  as  is  usually  done. 
Flues  should  never  in  any  case  be  made  less  than  '>|  inches  in 
depth.  Each  room  should  be  heated  by  a  separate  pipe.  In  some 
cases  however,  it  is  allowable  to  run  a  single  riser  to  lieat  two 
unimportant  rooms  on  an  upper  floor.  A  clear  space  of  at  least 
I  inch  should  be  left  between  the  risers  and  studs  and  the  latter 
should  be  carefully  tinned,  and  the  space  between  them  on  both 
sides  covered  with  tin,  asbestos  or  wire  lath. 

The  following  table  gives  the  capacity  of  oval  pipes.  A  6- 
inch  pipe  ovaled  to  5  means  that  a  6-inch  pipe  has  been  flattened 
out  to  a  thickness  of  5  inches  and  column  2  gives  the  resulting 
area. 

TABLE   VIL 


DIMENSION    OF    PIPE. 


AREA   IN    SQUARE   INCHES. 


6 

ovaled  to  5 

7 

"  4 

7 

"  31 

7 

"  6 

8 

"  b 

9 

"  4 

10 

"  3i 

9 

u  6 

9 

"  5 

11 

«  4 

12 

"  31 

10 

"  6 

11 

"  5 

14 

u  4 

15 

"  31 

12 

"  6 

12 

"  5 

19 

u   4 

20 

"  31 

27 
31 
29 
38 
43 
45 
46 
57 
51 
58 
55 
67 
67 
76 
73 
85 
75 
96 
100 


Having  determined,  the  size  of  round  pipe  required,  an  equiva- 


n 


IIKA'I'INC    AM)   \  KN'ni.A'noX. 


U'lil   i)V;il    pipo  iMM    1h'   st'liTtcd    ridiii    tlif    t;il)lt'    lo   suit    llic    s|>ac(^ 
aviiilahle. 

Registers.  Tln'  rcoisti-is  w  liicli  conlrol  the  siijiplv  ol  wanii 
air  to  lilt'  loiuns,  «;oiUMally  lia\r  a  lu-t  aita  ((lual  1<>  two-thirds  of 
their  j^M-oss  area.  Tlu"  lu-t  area  should  1k'  from  1<>  to  "Jd  percent 
j^reater  than  the  area  of  the  l>il)e  e;>nnc(lc(I  with  it.  It  is  coni- 
ni(»n  j)raetiee  to  nse  retjisters  having  the  short  (hiui'iision  (Mpial  to, 
and  the  h>ng  iliniension  al)out  one-half  greater  than  tlu;  diameter 
of  the  pipe.  This  would  give  the  following  standard  sizes  lor 
different  diameters  of  ]>ipe. 

TABLE    VIII. 


DIAMETER    OF   PIPE 


SIZE    OF    KEGISTEK. 


6 

6  X  10 

7 

7  X  10 

8 

8  X  12 

9 

9  X  14 

10 

10  X  15 

11 

11  X  16 

12 

12  X  17 

13 

14  X  20 

14 

14  X  22 

15 

15  X  22 

16 

10  X  24 

Combination  Systems.  A  combination  system  for  heating 
?J3'  hot  air  and  hot  water  consists  of  an  ordinary  fnrnace  with 
some  form  of  surface  for  heating  water,  placed  either  in  contact 
with  the  fire  or  suspended  above  it.  Fig.  84  shows  a  common 
iri-.mgement  where  part  of  the  heating  surface  forms  a  portion  of 
the  lining  to  the  fire  pot  and  the  remainder  is  above  the  fire. 

Care  must  be  taken  to  properly  proj)ortion  the  work  to  be 
done  by  the  air  and  the  water,  else  one  will  o[M;rate  at  the  expense 
of  the  other.  One  square  foot  of  heating  surface  in  contact  with 
the  fire  Is  capable  of  supplying  fioni  40  to  50  square  feet  of  radi- 
ating surface,  and  one  square  foot  suspended  over  the  fire  will 
supply  frtMu  1.^  to  25  square  feet  of  radiation. 

Care  and  Management.  The  foUowing  general  rules  ajipl}- 
to  the  management  of  all  hard  coal  furnaces. 


HEATING  AND  VENTILATION. 


45 


The  fire  should  be  thoroughly  shaken  once  or  twice  daily  in 
cold  weather.  It  is  well  to  keep  the  fire  pot  heaping  full  at  all 
times.  In  this  way  a  more  even  temperature  may  be  maintained, 
less  attention  required  and  no  more  coal  burned  than  when  the 


Fig.  34. 


pot  is  only  partly  filled.  In  mild  weather  the  mistake  is  fue- 
(juently  made  of  carrying  a  tliin  fire,  which  requires  frequent 
attention  and  is  likely  to  die  out.  Instead,  to  diminish  the  tem. 
perature  in  the  house,  keep  the  fire  pot  full  and  allow  ashes  to 
accumulate  on  the  grate  (not  under  it)  by  shaking  less  frequently 


-IG  IIKATING  AND  NKXTII.  A  TION. 


or  less  vigorouslv.  Vhc  a^^lu's  will  hold  ihc  licat  and  in-iitler  it  an 
ojisy  nmttov  ti)  inaintaiii  and  conliol  ilic  lin-.  Wlirn  t'eediug  coal 
on  a  low  lire,  o[)eii  the  limits  ami  noitlifr  rake  nor  shake  the  lire 
lill  the  fresh  eoal  beeomes  ignited.  The  air  sujiply  to  the  (ire  is 
of  the  greatest  importance.  An  insullicient  amount  results  in 
incomplete  combustion  and  a  great  loss  of  heat.  To  secure 
proper  combustion  the  tin'  slioukl  be  controlled  principally  by 
means  of  the  ash  pit,  through  the  ash  pit  door  or  slide. 

The  smoke  pi[)e  damper  should  l)e  ()[)encd  only  enough  to 
carry  olT  tlie  gas  or  smoke  and  to  give  the  necessary  diaft.  TIk; 
openings  in  the  feed  door  act  as  a  check  on  the  lii'c  and  sliould  be 
kept  closed  during  cold  weather,  ex,;e[)t  just  after  firing,  when 
with  a  good  draft  they  may  be  partly  opened  lo  inciease  the  air 
supply  and  promote  the  proper  combustion  of  the  gases. 

Keep  the  ash  pit  clear  to  avoid  war[)ing  or  melting  the  grate. 
The  cold-air  l)ox  should  be  kept  wide  open  except  during  winds 
or  when  the  lire  is  low.  At  sueh  times  it  may  be  partly,  but 
never  completely  closed.  Too  much  stress  cannot  be  laid  on  the 
imi)ortance  of  a  sufficient  air  supply  to  the  furnace.  It  costs 
little  if  any  more  to  maintain  a  comfortable  temperature  in  the 
house  night  and  day  than  to  allow  the  rooms  to  become  so  cold 
during  tlie  night  thai  the  fire  must  be  forced  in  the  morning  to 
warm  them  up  to  a  comfortable  temperature. 

In  case  the  warm  air  fails  at  times  to  reach  certain  looms 
it  may  be  forced  into  them  by  temporarily  closing  the  rt^gisters 
in  other  rooms.  The  current  once  established  will  generally  con- 
tinue after  the  other  registers  have  been  opened. 

It  is  best  to  burn  as  hard  coal  as  the  draft  will  warrant. 
Egg  size  is  better  than  larger  coal,  since  for  a  given  weight  small 
lumps  expose  more  surface  and  ignite  more  quickly  than  larger 
ones.  The  furnace  and  smoke  pipe  sliould  be  thoroughly  cleaned 
once  a  year.  This  should  be  done  just  after  the  fire  has  been 
allowed  to  go  out  in  the  spring. 

• 

STEAM  BOILERS. 

TypcH.  Tiie  boilers  used  for  heating  are  the  same  as  have 
already  been  described  for  power  work.      In  addition  there  is  the 


HEATING  AND  VENTILATION. 


47 


cast-iron   sectional   boiler,   which   is   almost   exclusively   used  for 
dwelling  houses. 

Sectional  Boilers.  Fig.  35  shows  a  common  form  of  cast- 
iron  boiler.  It  is  made  up  of  slabs  or  sections,  each  one  of  which 
is  connected  by  nipples  with  headers  at  the  sides  and  top.  The 
top  header  acts  as  a  steam  drum  and  the  lower  ones  act  as  mud 
drums ;  they  also  receive  the  water  of  condensation  from  the 
radiators.     The  gases  from   the  fire  pass  backward  and  forward 


Fig.  35. 


dirough  flues  and  are  finally  taken  off  at  the  rear  of  the  boiler.  The 
ratio  of  lieating  to  grate  surface  in  this  type  of  boiler  ranges 
from  15  to  25  in  the  best  makes.  They  are  provided  with  the 
usual  attachments,  such  as  pressure  gage,  water  glass,  gage  cocks 
and  safety  valve  ;  a  low-pressure  damper  regulator  is  furnished  for 
operating  the  draft  doors,  thus  keeping  the  steam  pressure  practi- 
cally constant.     A  pressure   of    from   1   to   5    pounds   is  usually 


48 


llK\'n\(;    AND   \  i:\ll  LA'iMoX. 


imitumI  oh  tlu'so  hollers  tlcju>ii(liii!j^  upon  the  outside  teMH)orature. 
I  lu"  usu;il  setliui,'  is  simply  ;i  eoveriuL,^  of  some  kind  of  non- 
oouilnetini,'  inuttMial  like  plastie  mat,niesia  or  asbestos,  altlioiiglv 
some  forms  are  em  dosed  in  light  brickwork.  Fig.  :}«>  shows  one 
of  this  kind  witli  part  of  the  setting  removed.  In  eom|)uting  the 
required  size  we  may  proceed   in  the  same  manner  as   in   the  case 


Fi<r.  36. 

of  a  furnace.  For  tlie  best  types  we  may  assume  a  combustion 
of  5  pounds  of  coal  per  square  foot  of  grate  per  lioui",  and  an 
average  efficiency  of  60  per  cent,  which  corresponds  to  8,000 
B.  T.  U.  per  pound  of  coal,  available  for  useful  work. 

In  the  case  of  direct  steam  heating  we  have  only  to  supply 
heat  to  offset  that  lost  l^y  radiation  and  conduction,  so  the  grate 
area  may  be  found  by  dividing  the  computed  heat  loss  per  hour  by 
8,000  which  gives  the  number  of  pounds  of  coal,  and  this  in  turn 
divided  by  o  will  give  the  area  (jf  grate  lerpiired.  The  most 
efficient  rate  of  combustion  will  depend  somew]>at  upon  the  ratio 
between   the  grate    HTid  heating  surface.     It  lias  been  found  by 


HEATING  AND  VENTILATION.  49 


experiment  that  about  |  of  a  pound  of  coal  per  hour  for  each 
scjuare  foot  of  heating  surface  gives  the  best  results,  so  that  by 
knowing  the  ratio  of  heating  surface  to  grate  area  for  any  make 
of  heater  we  may  easily  compute  the  most  efficient  rate  of  combus- 
tion and  from  it  determine  the  necessary  grate  area. 

For  example  —  The  heat  loss  from  a  building  is  480,000 
B.  T.  U.  per  hour ;  we  wish  to  use  a  heater  in  which  the  ratio  of 
heating  surface  to  grate  area  is  24,  what  will  be  the  most  efficient 
rate  of  combustion  and  the  required  grate  area?  480,000  ~  8,000 
=  60  pounds  of  coal  per  hour,  and  24  4-  4  =  6,  which  is  the  best 
rate  of  combustion  to  employ,  therefore  60  -4-  6  =:  10,  the  grate 
area  required. 

EXAIVIPLES  FOR    PRACTICE. 

1.  Tlie  heat  loss  from  a  building  is  240,000  B.  T.  U.  per 
hour  and  the  ratio  of  heating  to  grate  area  in  the  heater  to  be 
used  is  20,  wliat  will  be  the  required  grate  area?        Ans.  6  sq.  ft. 

2.  The  heat  loss  from  a  building  is  168,000  B.  T.  U.  per 
hour  and  the  chimney  draft  is  such  tliat  not  over  3  pounds  of  coal 
per  hour  can  be  burned  per  square  foot  of  grate.  What  ratio  of 
heating  to  grate  area  will  be  necessary  and  what  will  be  the 
required  grate  area?  Ans.  Ratio  12.     Grate  area  7  sq.  ft. 

Cast  iron  sectional  boilers  are  used  for  dwelling  houses,  small 
schoolhouses,  churches,  etc.,  where  low  pressures  are  carried. 
They  are  increased  in  size  by  adding  more  slabs  or  sections. 
After  a  certain  length  is  reached  the  rear  sections  become  less  and 
less  efficient,  thus  limiting  the  size  and  power. 

Tubular  Boilers.  Tubular  boilers  are  largely  used  for  heat- 
ing purposes,  and  are  adapted  to  all  classes  of  buildings  except 
dwelling  houses  and  the  special  cases  mentioned  for  which 
sectional  boilers  are  preferable.  The  capacity  of  this  type  of 
boiler  is  usually  stated  as  so  many  horse-power,  and  the  method  of 
determining  the  size  is  different  from  that  just  described.  A  boiler 
horse-power  has  been  defined  as  the  evaporation  of  34  ^  pounds  of 
water  from  and  at  a  temperature  of  212  degrees,  and  in  doing  this 
33,317  B.  T.  U.  are  absorbed,  which  are  again  given  out  when 
the  steam  is  condensed  in  the  radiators.  Hence  to  find  the  boiler 
H.  P.  required  for  warming. any  given   building  we  have  only  to 


50  I  IK  APING  AND  VENTILATION. 


i'oiu|>iiU'  tin*  luMt  loss  pi'i-  hour  l»y  the  nu'lhods  ahcatlr  _i,nvoii  and 
ilividf  the  nvsult  l»y  ;>;5,;>:1(>.  ji  is  more  t'oiimioii  lo  dividt'  by  the 
luiinhor  .'>.>, OOO,  whiv  h  jj^ivos  a  sliirhlly  larij^cr  hoih-r  and  is  on  the 
side  of  safety.  The  ratio  of  heating  to  ucrate  siirfaci^  in  this  type  of 
lK)iler  raiijj^es  from  ;50  to  40  and  therefore  allows  a  cond)iistioii  of 
from  8  to  10  pomids  of  i-oal  per  sipiare  fool  of  jjjrate.  This  is 
easily  ohtained  with  a  irood  chiniMev  draft  and  rareful  liriiitr. 
The  larufer  the  boiler,  the  more  iiuj)ortant  the  plant  usually,  and 
the  i,nealer  the  eare  bestowed  ujjon  it  so  that  we  may  generally 
eount  on  a  higher  rate  of  eombustion  ami  a  {greater  ellicicMiey  as 
the  size  of  the  boiler  increases.  The  following  table  will  be  found 
useful  in  determining  the  size  of  boiler  re(piired  under  dillfeiitnt 
i-onditions.  The  grate  area  is  computed  for  an  evaporation  of  8 
poumls  of  water  per  pound  of  coal,  which  corresponds  to  an  elli- 
eieuty  of  about  00  per  cent  and  is  about  the  average  obtained 
in  jirictice  for  heating  boilers. 

The  areas  of  uptake  and  smoke  pipe  are  figured  on  a  l)asis  of 
1  s(juare  foot  to  7  square  feet  of  grate  surface  and  the  results  given 
in  round  numbers.  In  the  smaller  sizes  the  relative  size  of  smoke 
pijte  is  greater.  The  rate  of  condjustion  runs  from  li  [jouiids  in 
the  smaller  sizes  to  11]  in  the  larger.  Boilers  of  the  proportions 
given  in  the  taljle,  correspond  well  with  those  used  in  actual 
practice  and  may  l^e  relied  upon  t(|  give  good  results  under  all 
ordinary  conditions. 

Water-tube  boilers  are  often  used  for  heating  purposes  l)ut 
more  especially  in  connection  with  power  plants.  The  method 
of  computing  the  recpiired  II.  P.  is  the  same  as  for  tubular 
boilers. 

Horse  Power  for  Ventilation.  We  already  know  that  one 
li.  r.  C  will  raise  the  temperature  of  1  cubic  foot  of  air  55  degrees, 
or  it  will  raise  100  cubic  feet  ^^^  of  55  or  -^^^  of  1  degree,  there- 
fore to  raise  100  cubic  feet  1  degree  it  will  take  1  -^  ^YV  ^'"  V/" 
B.  T.  U.,  and  to  raise  100  cubic  feet  through  lOO  degrees  it 
would  tiike  Ys"  X  100  B.  T.  U.  In  othei'  words,  the  li.  T.  [J.  re- 
quired to  raise  any  given  volume  of  air  through  any  number  of 
degrees  in  U'lnperature  is  equal  to 

Volume  of  air  in  cubic  ft.  X  Degrees  raised 
65        ''  ' 


HEATING  AND  VENTILATION. 


51 


TABLE  IX. 


Diameter      dumber 

of  shell         J  Tubes. 

in  Inches. 


30 


36 


42 


48 


Diameter 
of  Tubes 
in  Inches. 


28 


34 


34 


44 


54  54 


60 


66 


72 


46 

72 

64 
90 

78 

62 

114 

98 

72 


2>^ 


2>4 


Length 
of  Tubes 
in  Feet. 


'6/2 
3 


3 

4 
3 


10 


10 
11 
12 

9 
10 
11 
12 
13 
14 

10 
11 
12 
13 
14 

15 
16 

11 
12 
13 
14 
15 
16 
17 

12 
13 
14 
15 
16 
17 
18 

14 
15 
16 
17 
18 
19 
20 

14 
15 
16 

17 
18 
19 
20 


Horse 
Power. 


8.5 

9.9 

11.2 

12.6 

14.0 

13.6 
15.3 
16.9 
18.6 
20.9 

18.5 
20.5 
22.5 
24.5 
26.5 
28.5 

30.4 
33.2 
35.7 
38.3 
40.8 
43.4 
45.9 

34.6 
37.7 
40.8 
43.9 
47.0 
50.1 
53.0 

48.4 
52.4 
56.4 
60.4 
64.4 
71.4 
76.6 

70.1 
75.0 
80.0 
86.0 
91.1 
96.2 
93.1 

87.4 
93.6 
99.7 
106.4 
112.6 
118.8 
107.3 


Size  of  I  Size  of 
Grate  iu  '  Uptake 
Inches.    ,in  Inches, 


24x36 
24  X  36 
24  X  36 
24x42 

24x42 

30  X  36 
30  X  42 
30x42 
30  X  48 
30x48 

36x42 
36  X  42 
36  X  48 
36x48 
36  X  48 
36x54 

42  x48 
42  X  48 
42  X  54 

42  X  54 
42x60 
42x60 
42x60 

48x54 
48x54 
48  X  54 
48  X  54 
48x60 

43  X  60 
48x60 

54x60 
54  X  60 
54x60 
54x66 
54x66 
54x72 
54x72 

60x66 
60x72 
60x72 
60x78 
60x78 
60x78 
60x78 

66x72 
66x72 
66x78 
66  X  78 
66x84 
66x84 
66x84 


10x14 
10x14 
10x14 
10x14 
10x14 

10x16 
10x18 
10x18 
10x20 
10x20 

10x20 
10x20 
10x25 
10x25 
10x28 
10x28 

10x28 
10x28 
10  x  32 
10x32 
10  x  36 
10  X  36 
10x36 

10x38 
10x38 
10x38 
10  X  38 
10x40 
10x40 
10x40 


Size  of 

smokepipe 
in  sq.  in. 


12 

x40 

12 

x40 

12 

x40 

12 

x42 

12 

x42 

12 

x48 

12 

x48 

12 

x48 

12 

x52 

12 

x52 

12 

x56 

12 

x56 

12 

x56 

12 

x56 

12 

x56 

12 

x56 

12 

x62 

12 

x62 

12 

x66 

12 

x66 

12 

x66 

140  . 

140 

140 

140 

140 

160 
180 
180 
200 
200 

200 
200 
250 
250 
280 
280 

280 
280 
320 
320 
360 
360 
360 

380 
380 
380 
380 
400 
400 
400 

460 
460 
460 
500 
500 
550 
550 

500 
620 
620 
670 
670 
670 
670 

670 
670 
740 
740 
790 
790 
790 


52  111  MING  AND  VENTILATION. 


I'\;im|ili«    -  llnv  iiriiiv  l>. '1\  H.  :ir«'  ii'(]iiiit'(l  l(»  raist'.  100,000 
ruhif  It't't  of  air  "0  (ici^M-ccs  ? 

100,000  X  Tn 


1^7,-7:2  -I- 


Tit  ft>iu|mt<'  the  II.  r.  itMiuiit'd  ftir  the  vcntihilioii  of  a  Imild- 
'whj;  \vi'  multiply  tin"  total  air  supply  in  cubic  feet  pci-  hour  l)y  the 
mimlKM-  o{  degrees  through  which  it  is  to  be  raised,  and  divide  the 
ivsult  by  'yn.  This  gives  the  H.  T.  U.  per  hour,  which  divided 
l>y  3:^,000  will  give  the  II.  P.  required.  lu  using  this  rule  always 
take  the  air  snj)ply  iu  cubic  feet  j)cr  hour. 

EXAMPLES  FOR  PRACTICE. 

1.  The  heal  loss  from  a  Ijuilding  is  1,050,000  IL  T.  II.  per 
hour.  There  is  to  be  an  air  supply  of  1,500,000  cubic  feet  per 
hour,  raised  through  70  degrees. 

What  is  tlie  total  boiler  II.  P.  required?  Ans.   108. 

'2.  A  high  school  has  10  class  rooms,  each  occupied  by  50 
pupils.  Air  is  to  be  delivej-ed  to  the  I'ooms  at  a  temperature  of 
70  degrees.  What  will  be  the  total  H.  P.  required  to  heat  and 
ventilate  the  building  when  it  is  10  degrees  below  zero  if  the  heat 
loss  through  walls  and  windows  is  1,320,000   B.  T.  IJ.  per  hour? 

Ans.  106 +. 
DIRECT  STEAM  HEATING. 

Types  of  Radiating  Surface.  The  radiation  used  in  direct 
steam  heating  is  made  up  of  cast  iron  radiators  of  various  forms, 
pil>e  radiators  and  circulation  coils. 

Cast  Iron  Radiators.  The  general  form  of  cast  iron  sec- 
tional radiatoi-s  has  been  shown  in  Fig.  2.  They  are  made  up  of 
sections,  the  number  depending  upon  the  amount  of  heating  sur- 
face required.  Fig.  37  shows  an  intermediate  section  of  a  radiator 
of  this  t}-pe.  It  is  simply  a  loop  with  inlet  and  outlet  at  the 
lx>ttom.  The  end  sections  are  the  same,  except  they  have  legs  as 
shown  in  Fig.  38.  These  sections  are  coimected  at  the  bottom 
by  .special  nii)ple.s  so  that  steam  entering  at  the  end  fills  the 
W)ttom  of  the  radiator,  and  being  lighter  than  the  air  rises  through 
the  loops  and  forces  the  air  downward  and  toward  the  farther  end, 
where  it  is  discharged  through  an  air-valve  [)laced  about  midway 


HEATING  AND  VENTILATION. 


53 


of  the  last  section.  There  are  many  different  designs  varying  in 
height  and  width,  to  suit  all  conditions.  The  wall  pattern  shown 
in  Fig.  4  is  very  convenient  when  it  is  desired  to  place  the  radi- 
ator above  the  floor,  as  in  bath  rooms,  etc.  ;  it  is  also  a  convenient 
form  to  place  imder  the  windows  of  halls  and  churches  to  counteract 
the  effect  of  cold  down  drafts.  It  is  adapted  to  nearly  every  place 
where  the  oi'dinary  direct 
radiator  can  be  used  and  may 
be  connected  up  in  different 
ways  to  meet  the  various 
requirements. 

Pipe  Radiators.  This 
type  of  radiator  (see  Fig.  8) 
is  made  up  of  wrought  iron 
pipes  ^crewed  into  a  cast  iron 
base.  The  pipes  are  either 
connected  in  pairs  at  the  top 
by  return  bends  or  each  sepa- 
rate tube  has  a  thin  metal 
diaphragm  passing  up  tlie 
center  nearly  to  the  top.  It 
js  necessary    that  a  loop    be 

formed  else  a  "  dead  end  "  would  occur.  This  would  become  filled 
with  Wf  and  prevent  steam  from  entering,  thus  causing  portions 
of  tho  radiator  to  remain  cold.  For  a  given  surface  the  average 
'ji',)^,  ^idiator  is  moie  efficient  than  the  cast  iron  sectional  radiator. 


o 


Fier.  37. 


Fig.  38. 


Fig.  39. 

Circulation  Coils.  These  are  usually  made  up  of  1  or  1|- 
inch  wrought  iron  pipe,  and  may  be  hung  on  the  walls  of  a  room 
by  means  of  hook  plates  or  suspended  overhead  on  hangers  and 
rolls. 

Fig.  39  shows  a  common  form  for  schoolhouse  and  similar 


54 


iiKAiMNc  AM)  \i:n  rii.A'rioN. 


\vi>rk  ;  lliis  coil  is  usually  made  of  1  |-incli  I'ipf  screwed  into 
"lu'ailcis"  or  •>  hraucli  tecs"  at  the  ends,  and  is  liiniLj  on  the  wall 
just  Indow  the  windows.  'Phis  is  known  as  a  "hiauih  coil."  I'^io-, 
}<•  shows  a  '•  ti'omhone  coil,"  which  is  coMinionh  used  when  the 
pipes  cauuot  turn  a  coruer,  aud  where  the  eutire  coil  uui.st  he 
phieed  upon  one  .side  of  the  room.  Fig.  41  is  called  a  "  miter 
coil,"  and  is  used  under  the  same  conditions  as  a  trombone  coil  if 


Fijr.    40. 

there  is  room  for  the  vertical  portion.  This  form  is  not  as  pleas- 
ing in  appearance  as  either  of  the  other  two  and  is  only  found  in 
factories  or  shops  where  looks  are  of  minor  importance. 

Overhead  coils  are  usually  of  the  "  miter "  form  laid  on  the 
side  and  suspended  about  a  foot  from  the  ceiling ;  they  are  less 
efficient  than  when  placed  nearer  the  floor,  as  the  warm  air  stays 
at  the  ceiling  and  the  lower  part  of  the  room  is  likely  to  lemain 
cold.  They  are  only  used  when  wall  coils  or  radiators  would  be 
in  the  way  of  fixtures  or  when  they  would  come  below  the  water 


Fig.  41. 

line  of  the  boilei-  if  jilaced  near  the  floor.  A  coil  should  never 
be  made  up  :is  shown  in  Fig.  42,  as  unequal  expansion  of  the 
j'ij)e8  would  cause  strains  which  would  soon  result  in  leaky  joints. 
When  steam  is  first  turned  on  a  coil  it  usually  passes  through  a 
portion  of  the  pii)es  first  and  heats  them  while  the  others  remain 
cold  and  full  of  air.  Therefore  the  coil  must  always  be  made  up 
in  such  a  way  that  each  pipe  shall  have  a  certain  amount  of  spring 
and  may  expand  independently  without  bringing  undue  strains  upon 


HEATING  AND  VP^NTILATION. 


55 


the  others.  Circnhition  coils  should  incline-  about  1  inch  in  20 
feet  toward  the  return  end  in  order  to  secure  proper  drainage  and 
quietness  of  operation. 

Efficiency  of  Radiators.  The  efficiency  of  a  radiator,  that  is, 
the  B.  T.  U.  which  it  gives  off  per  square  foot  of  surface  per  hour, 
depends  upon  the  difference  in  temperature  between  the  steam  in 
the  radiator  and  the  surrounding  air,  the  velocity  of  the  air  over 
the  radiator,  and  the  quality  of  the  surface,  whether  smooth  or 
rough.  In  ordinary  low-pressure  heating  the  first  condition  is 
practically  constant,  but  the  second  varies  somewhat  with  the 
pattern  of  the  radiator.  An  open  design  which  allows  the  air  to 
circulate  freely  over  the  radiating  surfaces  is  more  efficient  than  a 
close  pattern  and  for  this  reason  a  pipe  coil  is  more  efficient  than 
a  radiator. 

In  a   large  number  of    tests  of  cast  iron  radiators,  working 


Fig.  42. 

under  usual  conditions,  the  heat  given  off  per  square  foot  of  sur- 
face per  hour,  for  each  degree  difference  in  temperature  between 
the  steam  and  surrounding  air,  w.is  found  to  vary  from  about  1.3 
to  1.7  B.  T.  U.  The  temperature  of  steam  at  3  pounds  pressure 
i?  220  degrees,  and  220  —  70  =  150,  which  may  be  taken  as  the 
average  difference  between  the  tem[)erature  of  the  steam  and  the 
air  of  the  room,  in  ordinary  low-pressure  work.  If  we  take  the 
mean  of  the  above  results,  that  is,  1.5  we  shall  have  150  X  1-5  = 
225  B,  T.  U.  as  the  efficiency  of  an  average  cast  iron  radiator.  A 
circulation  coil  made  up  of  pipes  from  1  to  2  inches  in  diameter 
will  easily  give  off  300  B.  T.  U.  under  the  same  conditions,  and 
a  shallow  pipe  radiator  of  standard  height  may  be  safely  counted 
upon  to  give  260.  These  efficiencies  are  lower  than  are  given  by 
some  (Migineers,  but  if  the  sizes  ai'c  taken  from  trade  catalogues  it 
is  not  safe  to  go  much  above  these  figures.  If  the  radiator  is  to 
be  us  m1  for  warming  rooms  which  are  to  be  kept  at  a  temperature 


ftC  IIKA  riNt.    AM)   \  KN  ril.AIMON, 


al»»»vc  ov  Ih'Iow  to  ilf^rt'cs,  llic  iiuliatiiii^  surface  iniiy  be  clianufcd 
in  tlio  saiiu'  proportion  as  the  tlitlt'icnce  in  tcnipcriituro  between 
llie  stetini  and  tlie  air. 

Viu-  fxanipli'  —  if  a  room  is  to  be  kept  ;it  u  temperature  of 
(U)^^  the  .'llirieney  of  the  radiator  becomes  \^'^  X  22;')  =  241  ; 
that  is  the  ethciency  varies  directly  as  the  iHlTerenee  in  temper- 
ature Ik'Iwccii  the  steam  and  the  air  of  the  room.  It  is  not  cus- 
U)maiy  to  I'onsider  this  unless  the  steam  pressure  should  be  raised 
to  10  or  If)  pounds  or  the  temperature  of  the  rooms  changed  15  or 
20  degrees  from  the  normal. 

From  the  above  it  is  easy  to  compute  the  size  of  i-adiator  for 
any  given  room.  First  compute  the  heat  loss  per  hour  by  radia- 
tion and  conduction,  in  the  coldest  weather,  then  divide  the  result 
by  225  for  ca.st  iron  radiators,  260  for  pipe  radiators  and  300  for 
pipe  coils.  It  is  customary  to  make  th'e  radiators  of  such  size, 
that  they  will  warm  the  rooms  to  70  degrees  in  the  coldest 
weather.  This  varies  a  good  deal  in  different  localities,  even  in 
the  same  state,  and  the  lowest  temperature  for  whicli  we  wish 
to  provide  must  be  settled  upon  before  any  calculatiojis  are  made. 
In  Xew  England  and  through  the  Middle  and  Western  States  it  is 
usual  to  figure  on  warming  a  building  to  70  degrees  when  the 
outside  temperature  is  from  zero  to  10  degrees  below. 

The  makers  of  radiators  pul)lish  in  their  catalogues,  tables 
giving  tiie  square  feet  of  heating  surface  for  different  styles  and 
heiglits,  and  these  can  l)e  used  in  determining  the  number  of 
sections  required  for  all  special  cases. 

If  pipe  coils  are  to  be  used,  it  becomes  necessary  to  reduce 
square  feet  of  heating  surface  to  linear  feet  of  pipe  ;  this  can  be 
duiut  by  means  of  the  factors  given  below. 

3      =  linear  ft.  of  1"    pipe 


Square  feet  of  heating  surface  X  < 


2.3  =      "         '^      1 1" 

2     =      "         u     11" 
1.6  =      "         "     2" 


The  size  of  radiator  is  only  made  sufficient  to  keep  the  room 
warm  after  it  is  once  heated,  and  no  allowance  is  made  for 
"warming  up,"  that  is,  the  heat  given  off  by  the  radiator  is  just 
equal  to  that  lost  through  walls  and  windows.  This  condition  is 
offset  in   two  ways  —  first,  when  the  room  is  cold,  the  difference 


HEATING  AND  VENTILATION. 


57 


in  temperature  between  the  steam  and  air  of  tlie  room  is  greater 
and  the  radiator  is  more  efficient,  and  second  the  radiator  is  pro- 
portioned for  the  coldest  weather  so  that  for  a  greater  part  of  the 
time  it  is  larger  than  necessary.  This  last  condition  is  one  of  the 
disadvantages  of  direct  steam  heating ;  if  steam  is  on  the  radiator 


at  all  it  will  give  off  the  same  amount  of  heat  regardless  of  the 
outside  temperature. 

EXAMPLES  FOR  PRACTICE. 

1.  The  heat  loss  from  a  room  is  22,500  B.  T.  U.  per  hour  in 
tlie  coldest  weather ;  what  size  of  direct  radiator  will  be  required  ? 

Ans.  100  square  feet. 

2.  A  schoolroom  is  to  be  warmed  with  circulation  coils  of  1|- 
inch  pipe.  The  heat  loss  is  30,000  B.  T.  U.  per  hour ;  what 
length  of  pipe  will  be  required  ?  Ans.  230  linear  feet. 

Location.  Radiators  should  be  placed  in  the  coldest 
part  of  the  room  if  possible,  as  under  windows  or  near  outside 
doors.  In  living  rooms  it  is  often  desirable  to  keep  the  windows 
free,  in  which  case  the  radiators  may  be  placed  at  one  side.  Cir- 
culation coils  are  run  along  the  outside  walls  of  a  room  under  the 


58  lIKATINi;    AND   \  I'.N  Tl  l,A  TION, 


wiiulows.  Sonu'binu's  llu'  position  of  the  nuliatoi-s  is  dt'cided  by 
the  nocos&iry  loi-ition  of  tln'  j>il>«'  risiM-s,  so  thai  a  lortain  amount 
of  judi,'nient  imist  hr  iisctl  in  each  s[>i'(ial  lasc  as  to  tliu  best 
arniugi'inent  to  suit  all   KMHiirenients. 

Systems  of  Pipinjj.  There  are  three  distinct  systems  of 
jtipini,',  known  as  the  "two-jtipe  systmn,"  the  "'one-pipe  relief 
system,'*  and  the  ••  ont'-[)i])e  ciri-uit  system,"  with  various  modifi- 
cations of  eaeh. 

Fig,  48  shows  the  arrangement  of  [)iping  and  ladiators  in  tiie 

two-pipe  system.     The  steam  main  leads  from  the  top  of  the  boiler 

and  the   branches  are  carried  along  near  the  basement  ceiling; 

risere  are  taken  off  from  the  supply  branches  and  carried  up  to  the 

STE^M  M^/N  radiators   on  the   differ- 

"^'  ent    floors,    and    return 

^  pipes  are  brought  down 

^  to    the    return     mains, 

J.^£_ which  should  be  i)laced 

near  the  basement  floor 
^  ^^      below  the  water  line  of 


_  _y^TER 

RETURN 


^*S-  44.  ti,g  i^^-^g,.^     Where  the 

building  is  more  than  two  stories  high,  radiatore  in  similar  posi- 
tions on  different  floors  are  connected  with  the  same  riser,  which 
may  run  to  the  highest  floor,  and  a  corresponding  return  drop 
connecting  with  each  radiator  is  carried  down  beside  the  riser  to 
the  basement,  A  system  in  which  the  main  horizontal  returns  are 
Ijelow  the  water  line  of  the  boiler  is  said  to  have  a  "  wet ''  or 
"sealed"  return.  If  the  returns  are  overhead  and  above  the 
water  line,  it  is  called  a  "dry"  return.  Where  the  steam  is  ex- 
jjosed  to  extended  surfaces  of  water,  as  in  overhead  returns,  where 
the  condensation  partially  tills  the  pipes,  there  is  likely  to  be 
cmcking  or  "  water  hammer  "  due  to  the  sudden  condensation  of 
the  steam  as  it  comes  in  contact  with  the  cooler  water.  This  is 
especially  noticeable  when  steam  is  first  turned  into  cold  pi[)es 
and  radiators,  and  the  condensation  is  excessive.  When  dry 
returns  are  used  the  pipes  should  be  large,  and  have  a  good  pitch 
toward  the  Ixnler. 

In  the  case  of  sealed   returns  the  only  contact  between  the 
steam   and  sUmding  water  Ls  in   the  vertical  returns  where   the 


HEATING  AND  VENTILATION. 


59 


exposed  surfaces  are  very  small  (being  equal  to  the  sectional 
area  of  the  pipjs)  and  trouble  from  water  hammer  is  practically- 
done  away  with.     Dry  returns  should  be  given  an  incline  of  at 


STE^M 


ID 


RC TURN 


^ 


SIPHON 


least  1    inch  in  10  feet, 

while  for  wet  returns  1 

inch  in  20  or  even    40    === 

feet     is     ample.        The 

ends  of  all  steam  mains 

and  branches  should  be 

dripped  into  the  returns. 

If  the  return   is  sealed, 

the  drip  may  be  directly  ^^8-  4o. 

connected  as  shown   in   Fig.  44,  but  if  it  is   dry,  the   connection 

should  bj  provided  with  a  siphon  loop  as  indicated  in  Fig.  45. 

The  loop   becomes    filled  with    water  and    prevents  steam    from 


*? 


ST€AM 


FifT.  46. 

flowing  directly  into  the  return.  As  the  condensation  collects  in 
the  loop  it  overflows  into  the  return  pipe  and  is  carried  away. 
The  return  pipes  in  this  case  are  of  course  filled  with  steam 
above  the  watei-,  but  it  is  steam  which  has  passed  through  the 
ladi'.itors  aiid  their  return  connections,  and  is  therefore  at  a  slightly 
lower  pressure,  so  that  if  steam  were  admitted  directly  from  the 


60 


Ill.AriM;    AM)   \  KNTILATION. 


iiiniii  it  would  ifiiil  to  liold  luii'k  llif  wMicf  in  iiioic  distiint  returns 
aiul  I'iiusi'  surixiiii,'  and  (  rackiiii;-  in  llui  pipes.  Sonictinios  the 
l»«)ilor  is  at  a  lower  \v\v\  llian  llie  l);isoinent  in  wliicli  iho  returns 
■,\\v  run  and  it  tlicti  lu-ronu's  ncct'ssaiy  to  cstnlilisii  ;i  >•  lalsc  water 
line,      'riii.s  is  done  liy  maUini;  coinieetions  as  shown  in  Kiu;'.  4<). 

It  i.s  readily  seen  that  the  retniii  water  in  order  to  reach  the 
hoiler  must  flow  over  the  looj)  "  .\  "  whiih  raises  the  water  line, 
or  seal,  to  the  level  sliown  by  the  dotted  line.  The  balance  pipe 
is  to  break  the  seal  as  the  water  Hows  over  the  loop,  and  prevent 


nini 


Fig.  47. 

anv  siphon  action  wliich  would  tend  to  drain  the  water  out  of  the 
return  mains  aft(M-  a  How  was  once  started. 

One-Pipe  Relief  System.  In  tliis  system  of  piping  the  radi- 
atoi-s  have  but  a  single  connection,  the  steam  flowing  in  and  the 
eondensation  draining  out  through  the  same  pipe.  Fig.  47  shows 
tlie  metliod  of  running  the  pipes  for  this  system.  The  steam 
main.  i\s  I)efore,  leads  from  the  top  of  the  boiler  and  is  carried 
to  as  high  a  point  as  the  basement  ceiling  will  allow  ;  it  then 
slo^ies  downward  with  a  grade  of  about  1  inch  in  10  feet  and 
makes  a  cinniit  of  the  building  oi-  a  portion  of  it. 

Risers  are  taken  off"  from  the  top  and  carried  to  the  ladiators 
alK)ve  as  in  the  two-pipe  system,  but  in  this  case,  the  condensation 


HEATING  AND  VENTILATION. 


61 


flows  back  through  the  same  pipe  and  drains  into  tlie  return 
main  near  the  floor  through  drip  connections  which  are  made  at 
frequent  intervals.  In  a  two-story  building  the  bottom  of  each 
riser  to  the  second  floor  is  dripped,  and  in  larger  buildings  it  is 
customary  to  drip  each  riser  that  has  more  than  one  radiator  con- 
nected with  it.  If  the  radiators  are  large  and  at  a  considerable 
distance  from  the  next  riser,  it  is  better  to  make  a  drip  connection 
for  each  radiator.  When  the  return  main  is  overhead,  the  risers 
should  be  dripped  through  siphon  loops,  but  the  ends  of  the 
branches  should  make  direct  connection  with  tiie  returns.  This 
is  the  reverse  of  the  two-pipe  system.      In  this  case  the  loAvest 


Fig.  48. 


pressure  is  at  the  ends  of  the  mains  so  that  steam  introduced 
into  the  returns  at  these  points  will  cause  no  trouble  in  the  pipes 
connecting  between  these  and  the  boiler. 

If  no  steam  is  allowed  to  enter  the  returns,  a  vacuum  will  be 
formed,  and  there  will  be  no  pressure  to  force  the  water  back  to 
the  l)oiler.  A  check  valve  should  always  be  placed  in  the  main 
return  near  the  boiler  to  prevent  the  water  from  flowing  out  in 
case  of  a  vacuum  being  formed  suddenly  in  the  pipes. 

One-Pipe  Circuit  System.  (See  Fig.  48.)  In  this  case  the 
steam  main  rises  to  the  highest  point  of  the  basement  as  before, 


62 


IIKATINC    AM)   VKNTILATIOM. 


ami  tluMi  with  a  iniuidtTahlc  ])it('h  makes  an  (Mitiic  liiiMiit  of  the 
buililint;  anil  ai^.iin  coniu'cts  with  tin-  hoih'r  hi'h)W  the  water  hnc. 
Sin«;U>  risn-s  are  taken  from  the  lop  and  the  eonih'nsation  drains 
Uu'k  thron<,'h  the  same  jjipes  and  is  carried  ah)ng  with  tiie  lh)w 
of  stoam  to   the  extreme  tMid  of  the  main,  where  it  is  returned  to 


Fig.  40. 


Fig.  50. 


tlie  boiler.  The  main  is  made  large  and  of  the  same  size  through- 
out its  entire  lengtli  :  it  must  be  given  a  good  pitch  to  insure 
satisfactory  results. 

One  objection  to  a  single-pipe  system  is  that  the  steam  and 
return  water  are  Rowing  in  opposite 
directions,  and  the  risers  nuist  be  made 
of  extra  large  size  to  prevent  any  in- 
terference. This  is  overcome  in  large 
buildings  by  carrying  a  single  riser  to 
tlie  attic,  large  enough  to  supply  the 
entire  building ;  then  branching  and 
running  "  drops  "  to  the  basement.  In 
this  system  the  flow  of  steam  is  down- 
ward as  well  as  that  of  water.  This 
method  of  piping  may  be  used  with 
good  results  in  two-pipe  systems  as  well.  Care  must  always  be 
laken  that  no  pockets  or  low  points  occur  in  any  of  the  lines  of 
pipe,  but  if  for  any  reason  they  cannot  Ije  avoided  they  should  be 
carefully  drained. 

Pipe  Connections.     Figs.  40,  50   and  51  show  the   common 
methods  of  Tiiaking  tlie  connections  between  the  supply  pipes  and 


Fig.  51. 


HEATING  AND  VENTILATION. 


G:i 


the  radiators.  Fig.  49  shows  a  two-pipe  connection  with  a  riser; 
the  return  is  carried  down  to  the  main  below.  Fig.  50  shows  a 
single  pipe  connection  with  a  basement  main  and  Fig.  51a  single 
connection  with  a  riser. 

Care  must  always  be  taken  to  make  the  horizontal  part  of  the 
piping  between  the  radiator  and  riser  as  short  as  possible  and  to 
ti-lve  it  a  good  pitch  toward  the  riser.  There  are  various  ways  of 
making  these  connections  especially  suited  to  different  conditions, 


B 


^UJ 


Fiff.  62. 


but  the  examples  given  serve  to  show  tlie  general  principle  to  be 

followed. 

Figs.  39,  40  and  41  show  the   common   methods  of  making 

steam  and  return  connections  with  circulation  coils.     The  position 

of  the  air  valve  is  shown  in  each  case. 

Expansion  of  Pipes.  Cold  steam  pipes  expand  approximately 
1  inch  in  each  100  feet  in  length  when  low  pressure  steam  is 
turned  into  tliem,  so  that  in  laying  out  a  system  of  piping  we 
must  arrange  it  in  such  a  manner  that  there  will  be  sufficient 
"spring"  or  "give"  to  the  pipes  to  prevent  injurious  strains. 
Tliis  is  done  by  means  of  offsets  and  bends.  In  the  case  of  larger 
pipes  this  simple  method  will  not  be  suffi  ient,  and  swivel  or  slip 
joints  must  be  used,  to  take  up  the  expansion.  The  method  of 
milking  up  a  swivel  joint  is  shown  in  Fig.  52. 

Any  lengthening  of  tlie  i)ipe  A  will  be  taken  up  by  slight 
turning  or  swivel  movements  at  tlie  points  B  and  C.     A  sli[)  joint 


C4 


llKAI'INii    AM)   \  K\  rih A'i'loN. 


is  shown  in  I'^Ili^.  ;">;>.  The  ]i;ii1  ■•  slich's  insi'K'  the  shell  </  and  is 
n»;ulo  steam  tii^ht  1>N'  a  stnllinL,'  hox  as  shown.  The  jtipes  aic  eon- 
iieeted  at  the  llaiii^es  A  and  H. 

\\  hen  pipes  j)ass  tlironi^h  lloois  oi-  partitions,  the  woodwork 
siiould  Ikj  proteetod  hv  galvani/.t'd  iron  sleevtis  havin<^  a  diameter 
from  3  to  1  ineli  <j;reater  than   the  pipe.      Vi^i;.  ;">  1  sliows  a   form  of 


Fig.  53. 

adjustable  floor  sleeve  wliich  may  be  lengthened  or  shortened  to 
conform  to  the  thickness  of  floor  or  partition.  If  plain  sleeves  are 
used,  a  plate  should  be  placed  around  the  pipe  where  it  passes 
through  the  floor  or  partition.      These  are  made  in  two  parts  so 

that  they  niay  be  put  in  place 
after  the  pi[)e  is  hung.  A  ])late 
of  this  kind  is  shown  in  Fig.  55. 
Valves.  The  difl^erent 
styles  commonly  used  for  radi- 
ator connections  are  shown  in 
Figs.  50,  57  and  58,  and  are 
known  as  "  angle,"  "  offset " 
and  "corner"  valves  respec- 
tively. The  first  is  used  when 
tlie  radiator  is  at  the  top  of  a 
riser  or  when  the  connections 
are  like  those  shown  in  Figs. 
49,  50  and  51  ;  the  second  is 
used  when  the  connection  l>etween  the  riser  and  radiator  is  above 
the  floor,  and  the  third  when  the  radiator  has  to  be  set  close 
in  the  comer  of  a  room  and  there  is  not  si)ace  for  the  usual  con- 
nection. A  fjlohe  valve  should  never  be  used  in  a  horizontal  steam 
supply  or   dry   return;    the   reason    for   this    is    plainly    shown    in 


HEATING  AND  VENTILATION, 


65 


Fig.  59.  In  order  for  water  to  flow  througli  the  valve  it  must 
rise  to  a  height  shown  by  the  clotted  line,  which  would  half  fill 
the  pipes,  and  cause  serious  trouble  from  water  hammer.  The 
gate  valve  shown  in  Fig.  60  does  not  have 
this  undesirable  feature,  as  the  opening 
is  on  a  level  with  the  bottom  of  the  pipe. 
Air  Valves.  Valves  of  various  kinda 
are  used  for  freeing  the  radiators  from  air 
when  steam  is  turned  on.  Fig.  61  shows 
simplest  form,  which  is  operated  by  hand. 
Fig.  62  is  a  type  of  automatic  valve  ;  it  consists  of  a  shell, 
which  is  attached  to  the  radiator.  B  is  a  small  openiug  which 
may  be  closed  by  the  spindle  C  which  is  piovided  with  a 
conical   end.      D  is   a   strip   composed  of  a  layer  of  iron  or  steel 


Fig.  56.  Fig.  57.  Fig.  58. 

and  one  of  brass  soldered  or  brazed  togetlier.  The  action  of  the 
valve  is  as  follows ;  when  the  radiator  is  cold  and  filled  with  air 
the  valve  stands  as  shown  in  the  cut.  When  steam  is  turned  on, 
the  air  is  driven  out  through  the  opening  B.  As  soon  as  this  is 
expelled  and  steam  strikes  the  strip  D,  the  two    prongs  spring 


Fig  59. 
apart  owing  to  the  unequal  expansion  of  the  two  metals  due  to 
the  heat  of  the  steam.  This  raises  the  spindle  G  and  closes  the 
opening  so  that  no  steam  can  escape.  If  air  should  collect  in  the 
valve  and  the  metal  strip  become  cool  it  would  contract  and  the 
spindle  would  drop  and  allow  the  air  to  escape   through  B  as  be- 


66 


IIKATINU  AND  VKNTILATION. 


foit».  K  is  an  adjusting  mil  :iiiil  1"'  is  ;i  lloal  atlat'luMl  Id  tlio 
spiiuUo,  ami  is  supposed  in  i-asc  of  a  sudden  nisli  of  water  with 
the  air  \o  rise  and  (dose  the  opening  ;  this  action  is  somewhat 
um-eitain,  especially  if  the  pressure  of  water 
t'ontinnes  for  some  time.  \_ 

There  are  other  types  of  valves  acting 
on  the  same  principle.  Tln^  valve  shown  in 
Fig.  63  is  closed  hy  the  expansion  of  a  })iece 
of  vulcanite  instead  t)f  a  metal  strip,  and  has 
no  water  float. 

The  valve  shown  in  Fig.  ()4  acts  on  a 
somewhat  different  principle.  The  float  C 
is  made  of  thin  brass,  closed  at  top  and  bot- 
tom, and  is  partially  tilled  with  wood  alcohol. 
When  steam  strikes  the  float  the  alcohol  is 
vaporized,  and  creates  a  pressure  sufficient 
to  Viulge  out  the  ends  slightly  which  raises 
the  spindle  and  closes  the  opening  li.  F'ig. 
6.')  shows  a  form  of  so-called  "vacuum' 
valve."  It  acts  in  a  similar  manner  to  those 
already  described,  but  has  in  addition  a  ball  check  which  prevents 
tlie  air  from  being  drawn  into  the  radiator,  shoidd  the  steam  go 
down  and  a  vacuum  be  formed.      If  a  partial  vacuum  exists  in  the 


v^ 


F\is:.  <il.  Fig.  63. 

boiler  and  radialois,  the  lx)iling  jjoint,  and  consequently  the 
U^'inperature  of  the  steam  are  lowered,  and  less  heat  is  given  off 
by  the  radiators.  Tliis  method  of  operating  a  heating  plant  is 
.sometimes  advocated  foi-  spring  and  fall  when  less  heat  is  re- 
<|uired,  and  steam   under  jjiessure  would  overheat  the  rooms. 

Pipe  Sizes.  The  pjoportioning  of  the  steam  pipes  in  a  heat- 
ing plant  is  of  the  greatest  importance,  and  should  be  carefully 
worked  out  by  methods  which  experience  has  proved  to  be  correct. 


Fia.  GO. 


HEATING  AND  VENTILATION. 


67 


There  are  several  ways  of  doing  this,  but  for  ordinary  condi- 
tions the  following  tables  have  given  excellent  results  in  actual 
practice.     They    have  been  computed  from  what   is    known   as 


Fig.  62. 


Fig.  65. 


D'Arcy's  formula,  with  suitable  corrections  made  for  actual  work 
ing  conditions.  As  the  computations  are  somewhat  complicated, 
only  the  results  will  be  given  here,  with 
full  directions  for  their  proper  use.  The 
following  table  gives  the  flow  of  steam  in 
pounds  per  minute  for  pipes  of  different 
diameters,  and  with  varying  drops  in 
pressure  between  the  supply  and  dis- 
charge ends  of  the  pipe.  These  quanti- 
ties are  for  pipes  100  feet  in  length;  for 
other  lengths  the  results  must  be  corrected 
by  the  factors  given  in  table  XII.  As  the 
length  of  the  pipe  increases,  the  friction 
becomes  greater,  and  the  quantity  of  steam 
discharged  in  a  given  time  is  diminished. 

Table  X  is  computed  on  the  assumption  that  the  drop  in 
pressure  between  the  two  ends  of  the  pipe  equals  the  initial  pres- 
sure.    If  the  drop  in  pressure  is  less  than  the  initial  pressure  tliu 


Fig.  64. 


OS 


iii;ai'i\(;  and  nkntil ation. 


ai'tnal  ilisohargo  will  be  slightly  greater  tlum  the  (Hiiiiililies  ujveii 
ill  the  tahle,  Imt  this  ilitTereiiee  will  be  .small  for  pii'ssuies  up  to 
•")  luuiiuls,  and  ean  Ix^  negleett'd  as  it  is  on  the  side  of  safety.  For 
higher  initial  pressures,  tiible  XI  has  been  prepared.       This  is  to 

TABLE  X. 


Pl.i: 

Drop  in  Pressure  (Pounds.) 

Of 

Pipe. 

H 

>4 

H 

1 

i'/2 

2 

3 

4 

6 

1 

.44 

.63 

.78 

.91 

1.13 

1.31 

1.66 

1.97 

2.26 

lU 

.81 

1.16 

1.43 

1.66 

2.05 

2.39 

3.02 

3.59 

4.12 

l}i 

1.06 

1.89 

2.34 

2.71 

3.30 

3.92 

4.94 

5.88 

6.75 

2 

2.93 

4.17 

5.10 

5.99 

7.43 

8.05 

10.9 

13.0 

14.9 

2J4 

5.29 

7.52 

9.32 

10.8 

13.4 

15.0 

19.7 

23.4 

20.9 

3 

8.61 

12.3 

15.2 

17.0 

21.8 

25.4 

32 

31.8 

43.7 

3!^ 

12.9 

18.3 

22.6 

26.3 

32.5 

37.9 

47.8 

56.9 

65.3 

4 

18.1 

25.7 

31.8 

30.9 

46.8 

53.3 

67.2 

80.1 

91.9 

5 

32.2 

45.7 

50.6 

05.7 

81.3 

94.7 

120 

142 

103 

6 

51.7 

73.3 

90.9 

100 

131 

152 

192 

229 

202 

7 

-6.7 

109 

135 

157 

194 

220 

285 

339 

390 

8 

108 

154 

190 

222 

274 

319 

402 

478 

549 

9 

147 

209 

258 

299 

371 

432 

545 

649 

745 

10 

192 

273 

339 

393 

487 

507 

715 

852 

977 

12 

305 

434 

537 

623 

771 

899 

1130 

1350 

15,50 

15 

535 

761 

942 

1090 

1350 

1580 

1990 

2370 

2720 

\)e  used  in  connection  with  table  X  as  follows.  First  find  from 
table  X  the  quantity  of  steam  which  will  be  discharged  through 
the  given  diameter  of  pipe  with  the  assumed  drop  in  pressure  ; 

TABLE  XL 


Initial  Pressure. 


Drop  in 

Pressure 

in  Pounds. 

10 

20 

30 

40 

60 

80 

1 

1.27 

1.49 

1.68 

1.84 

2.13 

2.38 

it 

1.26 

1.48 

1.66 

1.83 

2.11 

2.36 

i 

1.24 

1.46 

1.64 

1.80 

2.08 

2.32 

2 

1.21 

1.41 

1.59 

1.75 

2.02 

2.26 

3 

1.17 

1.37 

1.55 

1.70 

1.97 

2.20 

4 

1.14 

1.34 

1.51 

1.66 

1.92 

2.14 

5 

1.12 

1.31 

1.47 

1.62 

1.87 

2.09 

then  look  in  table  XI  for  the  factor  corresponding  with  the 
H.s3umed  drop  and  the  higher  initial  pressure  to  be  used.  The 
(piantity  given  in  table  X  multiplied  by  this  factor  will  give  the 
acfnal  capacity  of  the  pipe  under  the  given  condition.*!. 


HEATING  AND  VENTILATION. 


CD 


Example — What  weight  of  steam  will  be  discharged  through 
a  3"  pipe,  100  feet  long,  with  an  initial  pressure  of  60  pounds  and 
a  drop  of  2  pounds  ? 

Looking  in  table  X  we  find  that  a  3"  pipe  will  discharge 
25.4  pounds  of  steam  per  minute  with  a  2-pound  drop.  Then 
looking  in  table  XI  we  find  the  factor  corresponding  to  60  pounds 
initial  pressure  and  a  drop  of  2  pounds  to  be  2.02.  Then  accord- 
ing to  the  rule  given,  25.4  X  2.02  =  51.3  pounds  which  is  the 
capacity  of  a  3"  pipe  under  the  assumed  conditions. 

Sometimes  the  problem  will  be  presented  in  the  following 
way :  What  size  of  pipe  will  be  required  to  deliver  80  pounds  of 
steam  a  distance  of  100  feet  with  an  initial  pressure  of  40  pounds 
and  a  drop  of  3  pounds  ? 

TABLE  XIL" 


Feet. 

Factor. 

Feet. 

Factor. 

Feet. 

Factor. 

Feet 

Factor. 

10 

3.16 

120 

.91 

275 

.60 

600 

.40 

20 

2.24 

130 

.87 

300 

.57 

650 

.39 

30 

1.82 

140 

.84 

325 

.55 

700 

.37 

40 

1.58 

150 

.81 

350 

.53 

750 

.36 

50 

1.41 

160 

.79 

375 

.51 

800 

.35 

60 

1.29 

170 

.76 

400 

.50 

850 

.34 

70 

1.20 

180 

.74 

425 

.48 

900 

.33 

80 

1.12 

190 

.72 

450 

.47 

950 

.32 

90 

1.05 

200 

.70 

475 

.46 

1,000 

.31 

100 

1.00 

225 

.66 

500 

.45 

110 

.95 

250 

.63 

550 

.42 

We  have  seen  that  the  higher  the  initial  pressure  with  a 
given  drop,  the  greater  will  be  the  quantity  of  steam  discharged ; 
therefore  a  smaller  pipe  will  be  required  to  deliver  80  pounds 
of  steam  at  40  pounds  than  at  3  pounds  initial  pressure.  From 
table  XI  we  find  that  a  given  pipe  will  discharge  1.7  times  as 
much  steam  per  minute  with  a  pressure  of  40  pounds,  and  a  drop 
of  3  pounds,  as  it  would  with  a  pressure  of  3  pounds,  dropping 
to  zero.  From  this  it  is  evident  that  if  we  divide  80  by  1.7  and 
look  in  table  X  under  "  3  pounds  drop "  for  the  result  thus 
obtained,  the  size  of  pipe  corresponding  will  be  that  required, 

80^  1.7r=47. 


70  iii:.\ri\<;  and  \  iai'ii.aimon. 

I  lie  im;ih-si  iiiiiiilin  ill  llic  l;il)lt'  miiilvi'd  '■"'A  pounds  (lr(t[)  "  is 
I7.S  whii-h  i-ont'spoiids  to  ;i  l\},"  pipo  und  is  the  si/o  i-ecpiiii'd. 

I'lu'se  coiiditioiis  will  seldom  he  iiiel  with  in  low-pressure 
hiMliii^,  hut  apply  more  [ciriieulaily  to  eomhiiiatioii  powei-  and 
heatJMj,'  j)Iants,  and  will  he  taken  up  more  fidly  inider  tliaL  head. 
For  K> ninths  of  pipe  other  than  100  feet,  muh  i]ily  the  (puuitities 
Ufivi'ii  in  tahh'  X  hy  the  faetois  found  in  tahlc  XII. 

Example— What  weight  of  steam  will  he  disehaiged  per 
minute  through  a  S\"  pipe,  450  feet  long  with  a  pressure  of  5 
pounds  and  a  drop  of  \  j)ound  ? 

Tahle  X,  which  may  he  used  for  all  pressures  b<dow  10 
pounds,  gives  for  a  3^'  pipe,  100  feet  long,  a  capacity  of  18.3 
pounds  for  the  above  conditions.  Looking  in  tahle  XII,  we  find 
the  correction  factor  for  450  feet  to  l)e  .47.  Then  18.3  X  .47  = 
S.t't  pounds,  the  quantity  of  steam  which  will  he  discharged  if 
the  pipe  is  450  feet  long. 

Examples  involving  the  use  of  tables  X,  XI  and  XII  in 
condjination  are  quite  common  in  practice.  The  following  shows 
the  method  of  calculation  : 

What  size  of  pipe  will  be  required  to  deliver  90  pounds  of 
steam  per  minute  a  distance  of  800  feet,  with  an  initial  pressure 
of  80  pounds  and  a  drop  of  5  pounds?  Table  XII  gives  the 
factor  for  800  feet  as  .35  and  tal)le  XI  that  for  80  pounds  pres- 
sure and  5  pounds  drop  as  2.09.     Then z=  123  :  which 

.35  X  2.09 

is  the  equivalent  quantity,  we  must  look  for  in  table  X.  We 
find  that  a  4"  pipe  will  discharge  91.9  pounds,  and  a  5"  pipe  1G3 
pounds.  A  4.]"  pipe  is  not  commonly  carried  in  stock  and  we 
should  prol)ahly  use  a  5"  in  this  case,  unless  it  was  decided  to  use 
a  4"  and  allow  a  slightly  greater  drop  in  pressure.  In  ordinarj' 
heating  work  with  pressures  vaiying  from  2  to  5  pounds,  a  drop 
of  ^  pound  in  100  feet  has  been  found  to  give  satisfactory  results. 

In  computing  the  pipe  sizes  for  a  heating  system  by  the 
aliove  methods  it  would  he  a  long  process  to  work  out  the  size  of 
each  branch  separately  so  the  following  table  has  been  prepared 
for  ready  use  in  low-pressure  work. 

As  most  direct  heating  systems,  and  especially  those  in 
scliooUiouses,  are  made  up  of  Ijoth  radiators  and  ciiculation  coils, 


HEATING  AND  VENTILATION. 


71 


an  efficiency  of  300  B.  T.  U.  has  been  taken  for  direct  radiation 
of  whatever  variety,  no  distinction  being  made  between  the  dif- 
ferent kinds.  This  gives  a  slightly  larger  pipe  than  is  necessary 
for  cast  iron  radiators,  but  it  is  probably  offset  by  bends  in  the 
pipes,  and  in  any  case  gives  a  slight  factor  of  safety.  We  find 
from  a  steam  table  that  the  "  latent  heat "  of  steam  at  20  pounds 
above  a  vacuum,  (which  corresponds  to  5  pounds  gage-pressuie)  i, 
954  _|_  B.  T.  U.,  which  means  that  for  every  pound  of  steam  con- 
densed in  a  radiator  954  B.  T.  U.  are  given  off  for  warming  the 
air  of  the  room.  If  a  radiator  has  an  efficiency  of  300  B.  T.  U., 
then  each  square  foot  of  surface  will  condense  300  -^  954  =  314 
pounds  of  steam  per  liour,  so  that  we  may  assume  in  round  num- 
bers a  condensation  of  ^  of  a  pound  of  steam  per  hour  for  each 
square  foot  of  direct  radiation,  when  computing  the  sizes  of  steam 
pipes  in  low-pressure  heating.  Table  XIII  has  been  calculated  on 
this  assumption,  and   gives   the  square   feet   of   heating  surface 


TABLE    XIIL 

LENGTH    OF    PIPE 

100    FEET. 

Square  Feet  of  Heating  Surface. 

Size  of  Pipe. 

\  Pound  Drop. 

1  Pound  Drop. 

1 

80 

114 

1* 

145 

210 

190 

340 

2 

525 

750 

? 

950 

1350 

1550 

2210 

H 

4 

2320 

3290 

3250 

4620 

5 

5800 

8220 

6 

9320 

13200 

7 

13800 

19620 

8 

19440 

27720 

which  different  sizes  of  pipe  will  supply,  with  drops  in  pressure 
of  \  and  I  pounds,  in  each  100  feet  of  pipe.  The  former  should 
l)e  used  for  pressures  from  1  to  5  pounds,  and  the  latter  may  be 
used  for  pressures  over  5  pounds,  under  ordinary  conditions.     The 


iii'.ATixc  .\\i>  \i:\'iMi,  vnox. 


sizes   of    loiiLj    iiiaiiis    and    siiccial    j»i|>i's   of    1:iil;c    si/tr    should    lie 
proporlioiu'd  diivi'tly  t'ntiii  taMcs  \,  \1  mirl   Xll. 

Wlioii'  ilio  two-piiK'  systt'in  is  MSi'd  and  tlie  radiators  have 
separate  suj)|)ly  and  rotuni  jdpcs,  the  liscis  or  vertical  j)i[)es  may 
l»e  taken  from  table  Xill,  luit  it  tlie  siiiL^lc  |)ipe  s^-stein  is  used, 
the  risers  must  be  iuereascd  in  si/.e  as  the  steaui  aud  water  are 
tlowiiig  in  opposite  diri'ctions  and  nnist  have  plenty  of  room  to 
]>ass  eai'li  other.  It  is  eustomary  in  this  case  to  base  the  compu- 
tiition  on  the  velocity  of  the  steam  in  the  pij)rs  rather  than  on  the 
drop  in  pressure.  Assumint,ras  before,  a  condensation  of  one-third 
of  a  pound  of  steam  per  hour  per  sijuare  foot  of  radiation,  the  fol- 
lowing tables  have  been  prepared  for  velocities  of  10  aiul  15  feet 
per  second.  The  sizes  given  in  table  X\"  have  been  found  suffi- 
cient in  most  cases,  but  the  larger  sizes,  based  on  a  flow  of  10  feet 
per  second,  give  greater  safety  and  should  be  more  generally 
used.  The  size  of  the  largest  riser  should  usually  be  limited  to 
2.]"  in  school  and  dwelling  house  work  unless  it  is  a  special  pipe 
carried  up  in  a  concealed  position.  If  the  length  of  riser  is  short 
between  the  lowest  radiator  and  the  main,  a  higher  velocity  of  20 
feet  or  more  may  be  allowed  through  this  poition  lather  than 
niakf  tilt'  pipe  excessively  large. 

TABLE  XIV.  TABLE  XV. 


10  Feet  Per  Second  Velocity. 

15  Feet  Per  Second  Velocity. 

ijize  of  Pipe. 

Sq.  Feet  of  Radiation. 

Size  of  Pipe. 

Sq.  Feet  of  Radiation. 

1 

30 

1 

50 

n 

60 

H 

90 

u 

80 

1} 

120 

2 

130 

2 

200 

91 

190 

2^ 

290 

3 

290 

3 

340 

H 

390 

H 

590 

EXAMPLES  FOR  PRACTICE. 

1.  I  low  many  pounds  of  steam  will  be  delivered  per  minute, 
through  a  3^"  pipe  GOO  feet  long  with  an  initial  pressure  of  5 
pounds  and  a  drop  of  ^  pound.  Ans.   7.32  pounds. 

2.  What  size  pipe  \v:ll   be  recpiired  to  deliver  25.52   pounds 


HEATING  AND  VENTILATION. 


73 


of  steam  per  minute  with  an   initial  pressure  of  3  pounds  and  a 
drop  of  i  pound;  the  length  of  tlie  pipe  being  50  feet.    Ans.  4". 

3.  Compute  the  size  of  pipe  required  to  supply  10,000 
square  feet  of  direct  radiation,  (assume  |-  of  a  pound  of  steam  per 
square  foot  per  hour)  Avhere  the  distance  to  the  boiler  house  is 
300  feet  and  the  pressure  carried  is  10  pounds ;  allowing  a  drop 
in  pressure  of  4  pounds. 

Ans.  5".  (This  is  slightly  larger  than  is  required,  while  a 
4"  is  much  too  small.) 

TABLE  XVI. 


Dia.  of  Steam  Pipe. 

Dia.  of  Dry  Return. 

Dia.  of  Sealed  Return. 

1 

1 

4 

H 

1 

1 

n 

H 

1 

2 

H 

H 

3 

2 

^2^ 

I' 

H 

3 

2 

5 

3 

H 

6 

H 

3 

7 

H 

3 

8 

4 

n 

9 

5 

H 

10 

5 

4 

12 

6 

5 

Returns.  The  size  of  return  pipes  is  usually  a  matter  of 
custom  and  judgment  rather  than  computation.  It  is  a  common 
rule  among  steam  fitters  to  make 
the  returns  one  size  smaller  than 
the  corresponding  steam  pipes. 
Tliis  is  a  good  rule  for  the 
smaller  sizes,  but  gives  a  larger 
return  tlian  is  necessary  for  the 
larger  sizes  of  pipe.  Table  XVI 
gives  different  sizes  of  steam  pipes  Fig.  66. 

with    the  corresponding  diameters    for   dry   and   sealed    returns. 


74  iii:A'riN(;  and  \i:\'ni. a'imox. 


Tlic  li'ULi^ili  1)1"  run  and  nuniher  of  turns  In  a  roturn  pi[)0 
shouhl  1)0  notoil  and  any  unusual  condilions  providcil  for.  Where 
the  eondonsation  is  disehargcd  thioui^h  a  tra[)  into  a  lowi'r  pres- 
sure the  sizes  given  may  he  sliyrhlly  rtnhut'd,  especially  among  the 
larger  sizes,  depending  upon  the  dilTereni'e  in  |)ressnres. 

Uadiatoi-s  are  usually  tai)ped  for  pipe  connections  as  follows, 
and  these  sizes  nia\  he  useil  for  the  connections  with  the  mains  or 
rise  re. 

TWO-riPE    (CONNECTION. 

Return. 

■i" 
4 

3" 
4 

1    " 
W 


Square 

Feet  of  Radiation. 

Steam. 

10  to     oO 

3" 
4 

30  to    48 

1     " 

48  to    06 

H" 

96  to  150 

w 

SINC 

;le 

riPE    CONNECTION. 

10  to    24 

1    " 

24  to    60 

W 

60  to    80 

W 

80  tol.SO 

2  " 

Boiler  Connections.  The  steam  main  should  be  connected 
to  the  rear  nozzle,  if  a  tubular  boiler  is  used,  as  the  boiling  of  the 
water  is  less  violent  at  this  point  and  dryer  steam  will  be 
obtained.  The  shut-off  valve  should  be  placeil  in  such  a  position 
that  pockets  for  the  accumulation  of  condensation  will  be  avoided. 
Fig.  'o'o  shows  a  good  position  for  the  valve. 

The  return  connection  Ls  made  through  the  blow-off  pipe  and 
should  be  arranged  so  that  the  boiler  can  be  blown  off  without 
draining  the  returns.  A  check  valve  should  be  phiced  in  the 
main  leturn  and  a  l)lug  cock  in  the  blow-off  pijjc.  Fig.  67  shows 
in  plan  a  good  arrangement  for  these  connections. 

Blow-Off  Tank.  Where  the  blow-off  })ij)e  connects  with  a 
sewer  some  means  must  be  provided  for  cooling  the  water  or  the 
expansion  and  contraction  caused  by  the  hot  water  flowing 
thiough  the  drain  pipes  will  start  the  joints  and  cause  leaks.  For 
this  r«'«ison  it  is  customary  to  pass  the  water  through  a  blow-off 
tank.     A  form  of  wrought  iron  tank  is  shown    in    Fig.  68.     It 


HEATING  AND  VENTILATION. 


75 


The  tank 


consists  of  a  receiver  supported  on  cast-iron  cradles, 
ordinarily  stands  nearly  full  of  cold  water. 

The  pipe  from  the  boiler  enters  above  the  water  line,  and  the 
sewer  connection  leads  from  near  the  bottom  as  shown.  A  vapor 
pipe  is  carried  from  the  top  of  the  tank  above  the  roof  of  the 
building.     When  water  from  the  boiler  is  blown  into  the  tank 


c 


KIAIN     R£TUR» 


Si 

n 

<J 

\ 

vl 

■o 

tQ 

k 

Q 

5 

k 

r 

;^ 

t. 

TO  DRAIN  OR 


2 


BLOW-Orr    TANK 


Fig.  67. 
cold  water  from  the  bottom  flows  into  the  sewer  and  the  steam  is 
carried  off  through  the  vapor  pipe.  The  equalizing  pipe  is  to 
prevent  any  siphon  action  which  might  draw  the  water  out  of  the 
tank  after  a  flow  was  once  started.  As  only  a  part  of  the  water 
is  blown  out  of  a  boiler  at  one  time  the  blow-off  tank  can  be  of  a 
comparatively  small  size.      A  tank  24"  X  48"  should   be   large 


EQUAL/ZfNS 
^    PIPE 


^Z         )!y^If5^k'I^€--~f^- 


fP^±_BOtLEP_±^ 
—^      ^^^-^ 


Q 


tl 


TO  SEWER 


Fisr.  68. 


enough  for  boilers  up  to  48  inches  in  diameter  and  one  36" 
X  72"  should  care  for  a  boiler  72  inches  in  diameter.  If  smaller 
(quantities  of  water  are  blown  off  at  a  time  smaller  tanks  can  be 
used.  The  sizes  given  above  are  sufficient  for  batteries  of  2  or 
more  boilers,  as  one  boiler  can  be  blown  off  and  the  water  allowed 
to  cool  before  a  second  one  is  blown  off.  Cast  iron  tanks  are 
often  used  in  place  of  wrought  iron  and  these  may  be  sunken  in 
the  ground  if  desired. 


EXAMINATION  PAPER. 


HEATING  AND  VENTILATION 
PART  I. 


HEATING  AND  VENTILATION. 


Instructions  to  the  Student.  IMaco  your  iiumi'  and  lull  aililrt-ss  at  tlio 
lu'a»l  oi  till-  pain.!-.  Aviiitl  rnnvdiiif;  your  work  as  it  leads  to  t-rrors  and 
sliows  had  taste.  Mark  your  answers  plainly '"  Aiis."  Any  cheap,  li^ht 
l>ai>er  like  the  -ample  previously  sent  yon  may  he  used.  Alter  eomi)letin^ 
the  work  add  and  si;,Mi  the  l"(illn\vin<,f  statement. 

I  herehy  eertity  that  the  ahove  work  is  entirely  my  own. 

(Signed) 


1.  Wluil  ill  1  vail t;i<;e  does  indirect  steam  lieating  have  over 
direct  lieating?     What  advantages  over  furnace  heating? 

2.  What  are  the  causes  of  heat  loss  from  a  building? 

o.  Why  is  hot  water  es[)ecially  adapted  to  the  warming  of 
dwellings  ? 

4.  What  pro})ortion  of  carbonic  acid  gas  is  found  in  out- 
door air  under  ordinary  conditions? 

5.  A  room  in  the  N.  E.  corner  of  a  building  is  18'  s(iuare 
and  10'  high:  there  are  5  single  windows,  each  3'  X  10'  in  size. 
The  walls  are  of  brick  12"  in  thickness.  With  an  inside  temper- 
ature of  70  degrees  what  will  be  the  heat  loss  per  hour  in  zero 
weather?  Ans.   21,447  B.  T.  U. 

6.  State  four  important  points  to  be  noted  in  the  care  of  a 
fiiinaee? 

7.  A  grammar  school  building  has  4  rooms,  one  in  each 
corner,  each  being  30'  X  30'  and  14'  high  and  seating  50  pupils. 
The  walls  are  of  wooden  construction  and  the  windows  make  up 
,'j  of  the  total  expo.sed  surface.  The  basement  and  attic  are 
warm.  How  many  pounds  of  coal  will  be  required  per  hour  for 
I'oth  heating  and  ventilation  in  zero  weather  if  8O00  B.  T.  U.  are 
utilized  from  each  j)Ound  of  coal?  Ans.   r)()..'i  lbs. 

8.  What  two  distinct  types  of  furnaces  are  used?  What 
are  the  distinguishing  features? 

I>.  What  is  meant  by  the  efficiency  of  a  furnace?  What 
efficiencies  are  obtained  in  ordinary  practice;? 

10.  What    are    the    i>rincipal    parts    of    a    fiiniacc;?     State 
briefly  the  use  of  each. 

11.  .\   brick  hou.se  20' X  40'  has  3  stories,  each  10' high. 


HEATING  AND  VENTILATION.  79 

The  walls  are  12"  in  thichness  and  ^  the  total  exposed  wall  is 
taken  up  by  windows,  wliich  are  double.  The  basement  is  warm, 
but  the  attic  is  cold.  The  house  is  to  be  warmed  to  70  degrees 
when  it  is  ten  degrees  below  zero  outside.  How  many  square 
feet  of  grate  surface  will  be  required,  assuming  usual  efficiencies 
of  coal  and  furnace  ?  Ans.  8.5  square  feet. 

12.  A  high  school  is  to  be  provided  with  tubular  boilers. 
What  H.  P.  will  be  required  for  warming  and  ventilation  in  zero 
weather  if  there  are  600  occupants,  and  the  heat  loss  through 
walls  and  windows  is  1,500,000  B.  T.  U.  per  hour? 

Ans.  114.8 

13.  What  are  the  three  essential  parts  of  any  heating 
system  ? 

14.  Is  direct  steam  heating  adapted  to  the  warming  of 
schoolhouses  and  hospitals  ?     Give  the  reasons  for  your  answer. 

15.  The  heat  loss  from  a  dwelling  house  is  280,000  B.  T.  U. 
per  hour.  It  is  to  be  heated  with  direct  steam  by  a  type  of  boiler 
in  which  the  ratio  of  heating  surface  to  grate  surface  is  28. 
What  will  be  the  most  efficient  rate  of  combustion,  and  how 
many  squaie  feet  of  grate  surface  will  be  required? 

Ans.   7  pounds.      5  sq.  feet. 

16.  *What  is  the  use  of  a  blow-off  tank  ?  Show  by  a  sketch 
how  the  connections  are  made. 

17.  How  are  the  sizes  of  single  pipe  risers  computed? 

18.  What  weight  of  steam  will  be  discharged  per  hour 
tlirough  a  6"  pipe  300'  long  with  an  initial  presure  of  10  pounds 
and  a  drop  of  |  pound  in  its  entire  length  ?         Ans.  65.6  pounds. 

19.  What  is  an  air  valve?  Upon  what  principles  does  it 
work  ? 

20.  What  size  of  steam  pipe  will  be  required  to  discharge 
2400  pounds  of  steam  per  hour  a  distance  of  900',  with  an  initial 
pressure  of  sixty  pounds  and  a  drop  in  pressure  of  5  pounds  ? 

Ans.  31  dia. 

21.  What  objection  is  there  to  a  single  pipe  riser  system? 
How  is  this  sometimes  overcome  in  large  buildings  ? 

22.  Wliat  patterns  of  valves  sliould  be  used  for  radiators? 
What  conditions  of  construction  must  be  observed  in  making  the 
connections  between  the  radiator  and  riser  ? 


80  UK AI'ING  AND  VENTILATION. 


'2'-\.  riio  li»';it  loss  fioin  a  slioji  is  :'.i!,()()()  |).'!M  .  j)cr  hour; 
lii>\v  many  liiu'ar  Irct  of  -"  iiipt'  will  Ik-  icciiiiicd  to  warm  it,  tisiiij^ 
low  pivssuro  stciun?  Aiis.  \\)'2  h'.v.t. 

-I.  What  are  nu>aiit  ])y  "wet"  and  ''diy"  returns? 
Whieh  is  the  better,  and  why  '/ 

:2*).  How  many  liiieai'  feet  of  1["  |)i|)(!  are  required  to  give 
otY  the  same  amount  of  hiMt  as  a  east  iion  radiatoi"  having  125 
stjuare  feet  of  surface?  Ans.  21;')  feet. 

20.  What  tiiree  systems  of  pi{>ing  are  commonly  used  in 
direct  steanj  heating?     Describe  each  briefly. 

27.  What  is  a  "  branch  coil  ?  "  What  is  a  "  trombone  coil  ?  " 
In  what  cases  would  you  use  a  trombone  coil  instead  of  a  branch 
coil  ? 

28.  What  is  meant  by  the  ellieient:y  of  a  radiator?  Give 
average  efliciencies  of  cast  iron  and  pipe  radiators,  also  circulation 
coil. 

20.  The  heat  loss  from  a  room  is  22,500  H.T.U.  in  zero 
weather.  What  size  of  cast  iron  radiator  would  be  required  to 
warm  tlie  room  when  it  is  twenty  degrees  below  zero  ? 

Ans.  128  square  feet. 

30.  Where  would  you  place  the  direct  radiation  in  a  school- 
room ? 


HEATING  AND  VENTILATION 


PART    II 


INSTRUCTION     PAPER 


AMERICAN     SCHOOL     OF      CORRESPONDENCE 

[0HARTICRHX»    BY    THE    COMMONWEALTH    OF    MASSAOHCSETTs] 

BOvSTON,     MASSACHUSETTS 
U  .    S  .    A  . 


Prepared  By 

Charles  L.  Hubbard,  M.E., 

OF 

s.  homkr  woodhridge  company, 
Heating,  Ventilation  and  Sanitary  Engineers. 


HEATING  AND  VENTILATION. 


INDIRECT   STEAH   HEATING. 

Types  of  Heaters.  Various  forms  of  indirect  radiators  have 
been  shown  in  Figs.  8,  9, 14  and  15  of  Part  I,  A  hot-water  radiator 
may  be  used  for  steam  but  a  steam  radiator  cannot  always  be  used 
for  hot  water  as  it  nnist  be  especially  designed  to  produce  a  con- 
tinuous flow  of  water  through  it  from  top  to  bottom.     Figs.  1  and 


Fig.  1. 

2  show  the  outside  and  the  interior  construction  of  a  common 
pattern  of  indirect  radiator  designed  especially  for  steam.  The 
arrows  in    Fig.   2  indicate  the    path  of    the    steam   through    the 


Fio-.  2. 

radiator  which  is  supplied  at  the  right  while  the  return  connection 
is  at  the  left.  Tbe  air  valve  in  this  case  should  be  connected  in 
the  end  of  the  last  section  near  the  return. 

A  very  efficient  form  of  radiator  and  one  that  is  especially 
adapted  to  the  warming  of  large  volumes  of  air  as  in  schoolhouse 


IlKA'IMNi;    AND   \- KN  TI  I.ATIOK. 


\v«»i-k,  is  show  II  ill  V\^j;.  -^^  iiiul  is  known  as  llu'  "Scliool  pin  " 
nulijilor.  This  i-aii  lie  iisc^l  for  i-ilhrr  steam  or  liol  wait  r  as  there 
is  11  oontimious  passage  downwaiil  trom  liic  supply  eonneelioii  at 
the  top  to  the  return  at  the  hot  loin.  I'hese  sections  or  shil)s  are 
nuuh"  up  in  stacks  after  the  inaniicr  shown  in  i'l^^.    I   whicli  repre- 


sents an   end  view   of    seveial   sections   connected    together    with 
special  nipples. 

A  very  efficient  form  of  indire(;t  heater  may  be  made  np  of 
wrought  iron  pipe  joined  together  with  hranch  tees  and  icturn 
l)ends.  A  heater  like  that 
shown  in  Fig.  o  is  known  as  a 
''Itox  coil."  Its  efficiency  is 
increased  if  the  pipes  are 
"  staggered,''  that  is,  if  the 
pipes  in  alternate  row^s  are 
placed  over  the  spaces  between 
those  in  the  row  below. 

Stacks  and  Casings.  It 
has  already  been  stated  that  a 
group  (>{  sections  connected  to- 
gether is  calle<l  a  stack,  and  ex- 
amples of  these  with  their  casings  are  shown  in  Figs.  6  and  7  of 
Part  I.  The  ca.sings  are  usually  made  of  galvanized  iron  and  are 
made  up  in  sections  hy  means  of  small  bolts  so  that  they  may  be 
taken  apart  in  case  it  is  necessary  to  make  repairs.  Large  stacks 
are  often  enclosed  in  biick  work  ;  the  sides  consisting  of  8-inch  walls 
and  the  tr)p  Ijeing  covered  over  with  a  layer  of  bi-ick  and  mortar 


HEATING  AND  VENTILATION. 


supported  on  light  wrought  iron  tee  bars.  Where  a  single  stack 
supplies  several  flues  or  registers  the  connections  between  these 
and  the  warm-air  chamber  are  made  in  the  same  manner  as  already 
described  for  furnace  heating.  When  galvanized  iron  casings  are 
used  the  heater  is  supported  by  hangei-s  from  the  floor  above. 
Fig.  6  shows  the    method  of    lianging  a  heater   from  a  wooden 


S/DC     V/EW 


ENXI   \/lE\A/ 


Fig.  5. 

floor.  If  the  floor  is  of  fireproof  construction  the  hangers  may 
pass  up  througli  the  brickwork  and  the  ends  be  provided  with  nuts 
and  large  washers  or  plates  ;  or  they  can  be  clamped  to  the  iron 
beams  which  carry  the  floor.  Where  brick  casings  are  used,  tlie 
heaters  are  supported 
upon  pieces  of   pipe  or 


light  I-beams  built  into 
the  walls. 

Dampers.  Tlie 
general  arrangement  of 
a  galvanized  iron  casing 
and    mixing    damper  is 

shown  in  Fig.  7.  The  cold-air  duct  is  brought  along  the 
basement  ceiling  from  the  inlet  window  and  connects  with 
the  cold-air  chamber  beneath  tlie  heater.  The  entering  air 
passes  up  between  the  sections  ;ind  rises  tlirough  the  register 
above,  as  shown  by  the  arrows.  When  the  mixing  damper  is 
in  its  lowest  position  all  air  ivaching  the  register  must  pass 
through  the  heater,  but  if  the  damper  is  raised  to  the  ])osition 
shown,  part  of  the  air  will  pass  by  without  going  through  tlie 
heater  and  the  mixture  entering  through  the  register  will  be  at  a 
lower  temperature  than  before.  By  clianging  the  position  of  the 
damper  the  proportions  of    warm  and  cold  air   delivered  to  the 


WHO'T   IRON  PIPE 
Fig.  6. 


6 


IIKAIMN*;    AM)   VENTILATION. 


room  i-aii  In*  varicil,  ilnis  rci^ulatiiiL;'  (lu-  lt'iii|»(.'i-alui-('  without 
(liiuiiusliiiiLr.  to  any  LTifat  cxtciit,  tlic  (|Uaiitit\-  of  air  delivered. 
Tilt'   ol>j«'i'ti(m    to   this    foiin  of  dainpcr  is  that    there  is  a,  teinU'iicy 


rLOOn    R£G/ST£rR 


CALVAN/ZED  IRON      SLW/ZS/G  ZIOOR 
CAS/NG 

Fig.   7. 


for  the  air  to  enter  tlio  i-oom  hefoi'e  it  is  tJiorout^dily  mixed,  that 
is,  a  stream  of  warm  air  will  }ise  through  one  half  of  the  register 
while  cold  air  enters  through  the  other.     This  is  es[)eciallv  true  if 


Fig.  8. 


the  connection  between  the  damper  and  register  is  short.  Fig.  8 
shows  a  similar  heater  and  mixing  damper,  with  brick  casing. 
Cold  air  is  admitted  to  the  large  chanjber  below  the  heater  and 


HEATING  AND  VENTILATION. 


rises  through  the  sections  to  the  register  as  before.  The  action  ot 
the  mixing  damper  is  the  same  as  already  described.  Several 
flues  or  registers  may  be  connected  with  a  stack  of  this  form,  each 
connection  having  its  own  mixing  damper. 

The  arrangement  shown  in  Fig.  9  is  somewhat  different  and 
overcomes  the   objection  noted  in  connection  with  Fig.  7  by  sub- 


Fig.  9. 

stituting  another.  The  mixing  damper  in  this  case  is  placed  at 
the  other  end  of  the  heater.  When  it  is  in  its  highest  position 
all  of  the  air  must  pass  through  the  heater  before  reaching  the 
register,  but  when  partially  lowered  a  part  of  the  air  passes  over 
the  heater  and  the  result  is  a  mixture  of  cold  and  warm  air,  in 
proportions  depending  upon  the  position  of  the  damper.  As  the 
layer  of  warm  air  in  this  case  is  below  the  cold  air,  it  tends  to  rise 
through  it,  and  a  more  thorough  mixture  is  obtained  than  is  pos. 
sible  with  the  damper  shown  in  Fig.  8.  One  quite  serious 
objection  liowever  to  tliis  form  of 
damper  is  illustrated  in  Fig.  10. 
When  the  damper  is  nearly  closed 
80   that  the  greater  part   of  the    air  Fig.  10. 

enters  above  the  heater,  it  has  a  tendency  to  fall  between  the 
sections,  as  shown  by  the  arrows,  and  becoming  heated  rises  again, 
so  that  it  is  impossible  to  deliver  air  to  a  room  below  a  certain 
temperature.  This  peculiar  action  increases  as  the  quantity  of  air 
admitted  below  the  lieater  is  diminished.  When  the  inlet  register 
is  placed  in  the  wall  at  some  distance  above  the  floor,  as  in 
schoolhouse  work,  a  thorough  mixture  of  air  can  be  obtained  by 
placing  tl.e  heater  so  that  the  current  of  warm  air  will  pass  up  the 
front  of  the  flue  and  be  discharged  into  the   room  through  the 


iii:atim;  and  \  i:ntilation. 


\o\\vv  jiail  o(  llie  ivgister.  This  is  show  ii  (luiic  rU-aiiv  in  Fig.  11 
\vluMv  the  iMinvnt  of  wann  air  is  ivpiesi-uti'il  by  crooUed  arrows 
ami  the  cohl  iiir  by  straiglit  arrows.  The  two  currents  pass  up 
the  Hue  separately,  but  as  soon  as  they  are  discharged  through  the 
register  the  wann  air  tends  to  rise,  and  tlie  cold  air  to  fall,  with 
the  result  of  a  more  or  less  complete  mixtnre  as  shown. 

Il  i.^'ofien  desirable  to  warm  a  room  at  times  when  ventilation 


Jl 


Fitr.  11. 


is  not  neces.sary,  tis  in  the  case  of  living  rooms  during  the  night, 
or  for  quick  warming  in  the  morning.  A  register  and  damper  for 
air  rotation  should  be  piovided  in  this  case.  Fig.  12  shows  an 
arrangement  for  this  purpose.  When  the  damper  is  in  tlie  position 
shown,  air  will  be  taken  from  the  room  above  and  be  warmed  over 
and  over,  but  by  raising  the  damper,  the  supply  will  be  taken 


HEATING  AND  VENTILATION. 


from  outside.  Special  care  should  be  takeu  to  make  all  mixing 
dampers  tight  against  air  leakage,  else  their  advantages  will  be 
lost.  They  should  work  easily  and  close  tightly  against  flanges 
covered  with  felt.  They  may  be  operated  from  the  rooms  above 
by  means  of  chains  passing  over  guide  pulleys;  special  attach- 
ments should  be  provided  for  holding  in  any  desired  position. 

Size  of  Heaters.  The  efficiency  of  an  indirect  heater  depends 
upon  its  form,  the  difference  in  temperature  between  the  steam 
and  the  surrounding  air,  and  the  velocity  with  which  the  air 
passes  over  the  heater.  Under  ordinary  conditions  in  dwelling- 
house  work,  a  good  form  of  indirect  radiator  will  give  off  about 
2  B.  T.  U.  per  square  foot  per  hour  for  each  degree  difference  in 
temperature.  Assuming  a  steam  pressure  of  2  pounds  and  an 
outside  temperature  of  zero  we  should  have  a  difference  in  tem- 


Fig.  12. 

perature  of  about  220  degrees,  which  under  the  conditions  stated 
would  give  an  efficiency  of  220  X  2  =  440  B.  T.  U.  per  hour  for 
each  square  foot  of  radiation.  By  making  a  similar  computation 
for  10  degrees  below  zero  we  find  the  efficiency  to  be  460.  In 
the  same  manner  we  may  calculate  the  efficiency  for  varying  con- 
ditions of  steam  pressure  and  outside  temperature.  In  the  case 
of  schoolliouscs  and  similar  buildings  where  lai'ge  volumes  of  air 
are  warmed  to  a  moderate  temperature,  a  somewhat  higher  efficiency 
is  obtained  due  to  the  increased  velocity  of  the  air  over  the  heaters. 
Where  efficiencies  of  440  and  460  are  used  for  dwellings,  we  may 
substitute  600  and  620  for  school-houses.  This  corresponds 
approximately  to  2,7  B.  T.  U.  per  scjuare  foot  per  hour  for  a  differ- 
ence of  1  degree  between  the  air  and  steam. 

The  principles  involved  in  indirect  steam  heating  are  similar 


10  lIKAriXi;   AND  VKXTILATION. 


to  tluvJO  ulivaily  (lesorilu'il  in  furnace  heatiiii^.  P;ut  of  tlie  lieat 
i^iven  otT  bv  tlio  radiatur  must  be  used  in  warming  np  the  air 
siipplv  to  (he  temporatnie  of  tie  room,  and  \Y,ivt  foi-  olTsetting  the 
loss  by  eonduotion  tlirough  walls  and  w  indows.  Tlu^  method  of 
eiMUputing  the  heating  surface  recjuired,  (h'pends  u[)on  tlie  volume 
of  jiir  to  be  supplied  to  the  room.  In  the  case  of  a  schoolroom  or 
liall,  where  the  air  ([uantity  is  Lirge  as  com[)afe(l  with  the  ex- 
posed wall  and  window  surface  we  should  proceed  as  follows : 

First  compute  the  B.  T.  U.  required  for  loss  by  conduction 
through  walls  and  windows,  and  to  this  add  the  B.  T.  U.  required 
for  the  necessary  ventilation,  and  divide  the  sum  by  the  efficiency 
of  the  radiatoi-s.     An  example  will  make  this  clear. 

How  many  square  feet  of  indirect  radiation  will  be  required 
to  warm  and  ventilate  a  schoolroom  in  zero  weather,  where  the 
heat   loss  by  conduction    through  walls    and    windows  is  36000 
B.  T.  U.  and  the  air  supply  is  100,000  cubic  feet  per  hour?     By 
the  methods  given  under  "  Heat  for  Ventilation  "  we  have 
100,000  X  70,  ■,^^,^^_ 
65 
B.  T.  U.  required  for  ventilation. 

36,000  +  127,272  =  163,272  B.  T.  U.  =  the  total  heat  re- 
quired, and  this  in  turn  divided  by  600  (the  efficiency  of  indirect 
radiators  inider  these  conditions)  gives  272  square  feet  of  sui'face 
re'cjuired. 

In  the  case  of  a  dwelling-house  the  conditions  are  somewhat 
changed,  for  a  room  having  a  comparatively  large  exposure  will 
perhaps  have  only  2  or  3  occupants,  so  that  if  the  small  air  quan- 
tity necessary  in  this  case  was  used  to  convey  the  required  amount 
of  heat  U)  the  room,  it  would  have  to  be  raised  to  an  excessively 
high  temperature.  It  has  been  found  by  experience  that  the 
radiating  surface  necessary  for  indirect  heating  is  a])out  50  per 
cent  greater  than  that  required  for  .direct  heating.  So  for  this 
work  we  may  compute  the  surface  required  for  direct  radiation 
and  multiply  the  result  by  1.5. 

Buildings  like  hospitals  are  in  a  class  between  dwellings  and 
school  houses.  The  air  supply  is  based  on  the  number  of  occu- 
pants, as  in  schools,  but  other  conditions  conform  more  nearly  to 
dwelling  houses. 


HEATING  AND  VENTILATION.  11 


To  obtain  the  radiating  surface  for  buildings  of  this  class,  we 
compute  the  total  heat  required  for  warming  and  ventilation  as  in 
the  case  of  schoolhouses,  and  divide  this  sum  by  the  efRciencies 
given  for  dwellings,  that  is  440  for  zero  weather  and  460  for  10 
degrees  below. 

Example.  A  hospital  ward  requires  50,000  cubic  feet  of  air 
per  hour  for  ventilation,  and  the  heat  loss  by  conduction  through 
walls,  etc.  is  100,000  B.  T.  U.  per  hour.  How  many  square  feet 
of  indirect  radiation  will  be  required  to  warm  the  ward  in  zero 
weather. 

(50,000  X  70)  -4-  55  =  63,636  B.  T.  U.  for  ventilation  ;  then, 

63,636  +  100,000  ^  372  +  square  feet. 
440 

EXAnPLES  FOR  PRACTICE. 

1.  A  school  room  having  40  pupils  is  to  be  warmed  and 
ventilated  when  it  is  10  degrees  below  zero.  If  the  heat  loss  by 
conduction  is  30,000  B.  T.  U.  per  hour  and  the  air  supply  is  to 
be  40  cubic  feet  per  minute  per  pupil,  how  many  square  feet  of 
indirect  radiation  will  be  required  ?  Ans.  273. 

2.  A  contagious  ward  in  a  hospital  has  10  beds,  requiring 
6,000  cubic  feet  of  air  each,  per  hour.  The  heat  loss  by  conduc- 
tion in  zero  weather  is  80,000  B.  T.  U.  How  many  square  feet 
of  indirect  radiation  will  be  required  ?  Ans.  355. 

3.  The  lieat  loss  from  a  sitting  room  is  11,250  B.  T.  U.  per 
hour  in  zero  weather.  How  many  square  feet  of  indirect  radia- 
tion will  be  required  to  warm  it?  Ans.  75. 

Warm=Air  Flues.  The  required  size  of  the  warm-air  flue 
between  the  heater  and  the  register,  depends  first  upon  the  differ- 
ence in  temperature  between  the  air  in  the  flue  and  that  of  the 
room,  and  second,  upon  the  height  of  the  flue.  In  dwellings, 
hospitals,  etc.,  where  the  conditions  are  practically  constant,  it  is 
customary  to  allow  2  square  inches  area  for  each  square  foot  of 
radiation  when  the  room  is  on  the  first  floor,  and  1^  square  inches 
when  it  is  on  the  second  floor. 

In  schoolhouse  work  it  is  more  usual  to  calculate  the  size  of 
flue  from  an  assumed  velocity  of  air  flow  through  it.  This  will  vary 
greatly  according  to  the  outside  temperature  and  the  prevailing 


!•:  IIKATIXC    \\1)  VKXTILATION. 


wind  ooiuUtioiis.  Tlio  followiiiLT  futures  ni;iy  In'  lakcii  as  avoiage 
Vflofities  ol>taiiU'(l  in  piai'tioo,  aiul  iiiay  l)i'  used  as  a  basis  for  cal- 
oulatinij  tlu>  rc'iuirt'd  tlui>  arras  for  []\v  dilTerent  stories  of  a  school 
buiUliiii;. 

1st  lloor  280  feet  pci-  miiiiite. 

2iid    "     340     '*     - 

ard     '^     400     "     "         " 

These  velocities  Avill  be  increased  somewhat  in  windy  weatlier 
and  will  be  reduced  when  the  atmosphere  is  damp. 

Having  assumed  these  velocities,  and  knowing  the  number  of 
cubic  feet  of  air  to  be  delivered  to  the  room  per  minute,  we  have 
only  to  ilivide  this  (piantity  by  the  assumed  velocity,  to  obtain  the 
i"equired  tlue  area  in  s(|uare  feet. 

Example  —  A  schoolroom  on  the  second  iloor  is  to  have  an 
air  supply  of  2,000  cubic  feet  per  minute;  what  will  be  the 
required  flue  area? 

2000  ~  340  =  5.8  +  sq.  feet  Ans. 
The  velocities  would  be  higher  in  the  coldest  weather  and  dampers 
should  Ije  placed  in   the  flues  for  throttling  the  air  supply  when 
necessary. 

Cold-Air  Ducts.  The  cold-air  ducts  supplying  heaters  should 
be  planned  in  a  similar  manner  to  that  descri])ed  for  furnace  heat- 
ing. Tiie  air  inlet  should  be  on  the  nortli  or  west  side  of  the 
building,  but  this  of  course  is  not  always  possible.  The  method 
of  having  a  large  trunk  line  or  duct  with  inlets  on  two  or  more 
sides  of  the  building  .should  be  carried  out  when  })ossible.  A  cold- 
air  room  with  large  inlet  windows,  and  ducts  connecting  with  the 
heaters  make  a  good  arrangement  for  schoolhouse  work.  The 
inlet  ^^^ndows  in  this  case  should  be  provided  with  check  valves 
to  prevent  any  outward  flow  of  air.  A  detail  of  this  arrangement 
is  shown  in  Fig.  13. 

This  consists  of  a  ])oxing  around  the  window,  exten<ling  from 
the  floor  to  the  ceiling.  The  front  is  sloped  as  sliown  and  is 
closed  from  the  ceiling  to  a  point  below  the  bottom  of  the  window. 
The  remainder  is  open  and  covered  with  a  wire  netting  of  about 
\  inch  mesh ;  to  this  are  fastened  flaps  or  checks  of  gossamer 
cloth  alx)ut  6  inches  in  width.  These  are  heninuMl  on  both  edges 
and  a  stout  wire  is  run  tlirough  the  upper  hem  which  is  fastened 


HEATIXG  AND   VEXTILATION. 


13 


to  the  nettincr  bv  means  of  small  copper  or  soft  iron  wire.  The 
checks  allow  the  air  to  flow  inward  but  close  when  there  is  any 
tendency  for  the  current  to  reverse. 

The  ai-ea  of  the  cold-air  duct  for  any  heater  should  ]je  atout 
three-fourtlis  the  total  area  of  the  warm  air  ducts  leading  from  it. 
\  common  rule  for  dweUing  houses  and  similar  work  is  to 
allow  11  square  inches  of  area  for  each  square  foot  of  i-adiatmg 
surface.'  The  inlet  windows  should  be  provided  ^mh  some  form 
of  damper  or  slide, 
outside  of  which 
should  be  placed  a 
wire  grating,  backed 
by  a  netting  of  about 
3  inch  mesh. 

Vent  Flues.  In 
dwelling  houses  vent 
flues  are  often  omitted 
and  the  frequent  open- 
inor  of  doors  and  leak- 
age  are  depended 
upon  to  carry  away 
the  impuie  air.  A 
well  designed  system 
of  warming  should 
provide   some    means 

for  discharge  ventilation,  especiaUy  for  bath  and  toilet  rooms,  and 
also  fDr  living  rooms  where  lights  are  burned  in  the  evening. 
The  sizes  of  flues  may  be  made  the  reveree  of  the  warm-ak  flues, 
that  is,  11  square  inches  area  per  square  foot  of  indiiect  i-adiar 
tion  for  rooms  on  the  first  floor  and  2  square  inches  for  those 
on  the  second.  This  is  because  the  velocity  of  flow  will  de- 
pend upon  the  height  of  flue  and  ^vill  therefore  be  greater  from 
the  first  floor.  The  flues  should  l>e  joined  together  in  the  attic 
and  then  carried  tlirough  the  roof  where  a  ventHating  hood  should 
be  provided,  especiaUy  designed  to  keep  out  the  rain  and  snow.  A 
good  form  is  slio^-n  in  Fig.  14. 

Verv  good  results  may  be  obtained  by  simply  letting  the  flues 
open  into  an  unfinished  attic  and  depending  upon  leakage  through 


;^^^^:^^^^^^^^^^^^^^^ 


Fis.  13. 


14 


IIKATINC    AND   \' KXTI  I.A'IMON. 


WluTl'     tint 


ilif  vooi  [o  awry  away  tlu'  foul  aii.  Tin-  ll<i\\  of  air  tlirouj^h  the 
vents  will  Iff  slow  at  ln'st  unless  some  ineaus  is  proNided  Idi- wai'iii- 
iM»;  the  air  in  the  line  to  a  lenipei'at  ure  ahove  thai  of  (he  room  with 
whii'h  it  eouneits.  'I'his  may  ln'  »h)ne  i)y  caiiyiiiL;'  up  a  loop  ol" 
stoam  pilH'  inside  of  the  line.  it  sluudd  he  conneekHl  for  ihain- 
a»:;-e  and  air  ventin<^  as  shown  in  V'\'j;.  IT). 

For  sehoolhouse  work  we  may  assume  average  velocities 
througli  the  vent  flues  as  follows  : 

Ist  floor  340  feet  per  miu. 
2nd  -     280     ''      "       « 
3rd    "     220      "      "       " 

sizes  are  hased  on  these  velocities  it  is  well  to 
H'uard  against  down  drafts  hy  plac- 
ing an  aspirating  eoil  in  the  flue. 
A  single  row  of  pipes  across  the  flue 
as  shown  in  Fig.  16  is  usually  suffi- 
cient for  this  purpose.  The  slant 
height  of  the  heater  should  be  about 
twice  the  depth  of  the  flue  so  that 
the  area  between  the  pipes  shall  equal 
the  free  area  of  the  flue. 

Large  vent  flues  of  this  kind 
should  always  be  provided  with  dam- 
pers for  closing  at  night  and  for 
regulation  during  strong  winds. 
Sometimes  it  is  desired  to  move  a  given  quantity  of  air  through 
a  flue  which  is  already  in  place. 

Table  I  shows  what  velocities  may  be  obtained  through 
flues  of  different  heights  for  varying  differences  in  temperature 
between  the  outside  air  and  that  in  the  flu(;. 

Example.  —  It  is  desired  to  discharge  1300  cubic  feet  of  air 
per  minute  through  a  flue  having  an  area  of  4  square  feet  and  a 
height  of  30  feet.  If  the  efficiency  of  an  aspiiating  coil  is  400 
B.  T.  U.  how  many  square  feet  of  surfaje  will  be  required  to 
move  this  amount  of  air  when  the  temperature  of  the  room  is  70° 
and  the  outside  temperature  is  00°  ? 

1300  4-  4  r=  325  feet  per  minute  =:  velocity  through  the 
flue.     Looking    in    table   I   and  following  along  the  line   oppo- 


Fig.   14. 


HEATING  AND  VENTILATION. 


15 


site  a  30-foot  flue  we  find  that  to  obtain  this  velocity  there  must 
be  a  difference  of  30  degrees  between  the  air  in  the  flue  and  the 
external  air.  If  the  outside  temperature  is  60  degrees  then  the 
air  in  the  flue  must  be  raised  to  60  +  30  =  90  degrees.     The  air 

TABLE  L 


Height  of 

Flue  in 

Feet. 


5 
10 

15 

20 
25 
30 
35 
40 
45 
50 
60 


Excess  of  Temperature  of  Air  in  Flue  above  that  of  External  Air. 


10° 


55 
77 
94 
108 
121 
183 
143 
153 
162 
171 
188 


76 
108 
133 
153 
171 
188 
203 
217 
230 
242 
264 


15<= 


94 
133 

162 

188 
210 
230 
248 
265 
282 
297 
325 


20° 


109 
153 

188 
217 
242 
265 
286 
306 
325 
342 
373 


30° 


134 

188 
230 
265 
297 
325 
351 
375 
398 
419 
461 


50° 


167 
242 
297 
342 
383 
419 
453 
484 
514 
541 
594 


of  the  room  being  at  70  degrees,  a  rise  of  20  degrees  is  necessary, 
so  the  problem  resolves  itself  into  the  following  —  What  amount 
of  heating  surface,  having  an  einciency  of  400  B.  T.  U.  is  neces- 


Fig.  15. 

sary  to  raise  1300  cubic  feet  of  air  per  minute  through  20  degrees  ? 
1300  cubic  feet  per  minute  =  1300  X  60  =  78,000  per  hour, 


IG 


IIKAIMNG  AND  VENTILATION. 


ami    in.ikiii"-   use   of    mir  rtuimil.i   l'i)r    *•  IumI    I'oi-    vcntilatu)ii,''    wo 
have 

WOO  x^o  _,.,,,, ^ 

a 
and    this   div'nUMl   hy   40(1  =  71    s(|iiiuo   feet   of    lieatint^   surface 
iiHjuired. 


FRONT      V/£W 


S/DC     V/CV^ 


VV'    16. 


EXAMPLES  FOR  PRACTICE. 

1.  A  school  rf)oin  on  tlie  3(1  floor  has  50  pupils  which  are 
to  be  furnished  with  30  cubic  feet  of  air  per  minute  each.  What 
will  1)6  the  re(pured  areas  iu  square  feet  of  the  supply  and  vent 
flues?  Ans.  Supply  3.7  +.     Vent  6.8  +. 

2.  What  size  of  heater  will  be  required  in  a  vent  flue  40 
feet  high  and  with  an  area  of  5  sipiare  feet,  to  enable  it  to  dis- 
charge lo30  cubic  feet  per  minute,  when  the  outside  temperature 
is  tiO'^  ?     (Assume  an  efliciency  of  400  B.  T.  U.  for  the  heater.) 

Ans.  41.7  square  feet. 
Registers.  Registers  are  made  of  cast  iron  and  bronze,  in  a 
great  variety  of  sizes  and  patterns.  The  universal  finish  for  cast 
iron  is  black  "  Japan  "  ;  they  are  also  finished  in  colors  and  electro- 
plated with  copper  and  nickle.  Fig.  17  shows  a  section  through 
a  floor  register  in  which  "A"  represents  the  valves,  which  may  be 
turned  in  a  vertical  or  horizontal  position,  thus  opening  or  closing 
the  register ;  "  li  "  is  the  iron  Ijorder,  "  C  "  the  register  box  of  tin 
or  galvanized  iron  and  •'  D  "  tlie  warm-air  pipe.      Floor  registers 


HEATING  AND  VENTILATION. 


17 


are  usually  set  in  cast  iron  borders,  one  of  which  is  shown  in  Fig. 
18,  while  Avail  registers  may  be  screwed  directly  to  wooden  borders 
or  frames  to  correspond  with  the  finish  of  the  room.  Wall  regis- 
ters should  be  provided  with  j^uU  cords  for  opening  and  closing 
from  the  floor ;  these  are  shown  g  g 

in  Fig.  19.  The  plain  lattice 
pattern  shown  in  Fig.  20  is  the  J 
best  for  schoolhouse  work  as  it 
has  a  comparatively  free  open- 
ing for  air  flow  and  is  pleasing 
and  simple  in  design.  More  ^^^ 
elaborate  patterns  are   used  foi-  ^^S-  l"^- 

fine  dwelling-house  woik.  Registers  with  shut-off  valves  are 
used  for  air  inlets  while  the  plain  register  faces  without  the  valves 
are  placed  in  the  vent  openings.     The    vent   flues    are    usually 


Fig.  18. 
gathered  together  in  the  attic  and  a  single  damper  may  be  used  to 
shut  off  the  whole  number  at  once.  Flat  or  round  wire  gratings 
of  open  pattern  are  often  used  in  place  of  register  faces.  The 
grill  or  solid  part  of  a  register  face  usually  takes  up  about  i  of  the 
area,  hence  in  computing  the  size  we  must  allow  for  this  by  multiply- 
ing the  required  "net  area"  by  1.5  to  obtain  the  "total"  or 
"  over  all  "  area. 

For  example,  suppose  we  have  a  flue  10  inches  in  width  and 


18 


IIKA'IMXC    AND   \KX'ril. A'IMOX. 


wish  to  uso  :i  ivj^istor  luivini;  a  froe  area  of  '200  sciuare  inches, 
what  will  l>o  tlu'  ivquiivd  luMght  of  the  register?  200  X  1.5  =  300 
stjuare  iiulu-s  wliicli  is  the  total  area  retpiired,  then  300  -^-  10  =  30, 
whieli  is  tlu"  rei[uir»'(l  height  and  we  should  use  a  10"  X  30" 
register.  When  a  register  is  spoken  of  as  a  10"  X  30"  or 
10"  X  -0",  et€.  the  dimensions  of  the  lattieed  oix-iiing  is  meant, 
and  not  the  outside  dimensions  of  tlu^  whole  register.  The  free 
opening  should  have  the   same    area  as    ilic    Hii(>   with   wliich  it 


SC  jKxacac  2 


VcNTlLATORj 

FOR 

CORDS 


r 


■■■■■■■■ 
■■DBHIB 

■BHHBBBH 
■■■'■■■■■ 
■■■■■■■■ 

■■■■■■■■ 
■■■■■■■■ 

■■■■■■■■ 

I  MM  BS-8SB  H 


connects.  In  designing  new  work  one  should  provide  himself 
with  a  trade  catalogue,  and  use  only  standard  sizes  as  special 
patterns  and  sizes  are  costly.  Fig.  21  shows  the  method  of 
I)lacing  gossamer  check  valves  back  of  the  vent  register  faces 
to  prevent  down  drafts,  the  same  as  described  for  fresh-air  inlets. 
Pipe  Connections.  The  two-pipe  system  with  dry  or  sealed 
returns  is  used  in  indirect  heating.  The  conditions  to  be  met  are 
practically  the  same  as  in  direct  heating,  the  only  difference  being 
that  the  radiators  are  at  the  basement  ceiling  instead  of  on  the 
floors  alxive.  The  exact  method  of  making  the  pipe  connec- 
tions will    dei>end  somewhat    upon    existing  conditions,  but  the 


HEATING  AND  VENTILATION. 


19 


general  method  shown  in  Fig.  22  may  be  used  as  a  guide  with 
modifications  to  suit  any  special  case.  The  ends  of  all  supply 
mains  should  be  dripped,  and  the  horizontal  returns  should  be 
sealed  if  possible. 

Pipe  Sizes.  The  tables  already  given  for  the  proportioning 
of  pipe  sizes  can  be  used  for  indirect  systems.  The  following 
table  has  been  computed  for  an  efiicienc}^  of  640  B.  T.  U.  per 
square  foot  of  surface  per  hour,  which  corresponds  to  a  condensa- 


QOSSAMER 
CHECKS 


WIRE 
NETT/NG 


Fig.  21. 
tion  of  ^  of  a  pound  of  steam.     This  is  twice  that  allowed  for 
direct  radiation  in  table  XIII.  of  Part  I.,  so  that  we  can  consider 
1  square  foot  of  indirect  surface  as  equal  to  2  of  direct  in  com- 
puting pipe  sizes. 

As  the  indirect  heaters  are  placed  in  the  basement,  care  must 
be  taken  that  the  bottom  of  the  radiator  does  not  come  too  near 
the  water  line  of  the  boiler,  or  the  condensation  will  not  flow  back 
properly;  this  distance  should  not  be  less  than  2  feet  under 
ordinary  conditions.  If  much  less  than  this,  the  pipes  should  be 
made  extra  large  so  there  may  be  little  or  no  drop  in  pressure 


•20 


1TKATI\(;   A\n  VKNIMl.ATIOX. 


IvtwtH'ii  tlu'  IxiiltT  ;iiitl  llu-  luMh'i'.      A  (li(i|)  ill  pressure  ot   1  poiiiul 
woulil  raisi"  tlu'  wali-r  liiu'  at  llio  licalir  "J.  I  t'lH't. 

Direct-Indirect  Heatinj!:.  'V\\e  q-t'iu'ial  form  df  a  direct- 
iiuliroit  railialor  lias  bt'oii  shown  in  l''ii;s.  1(1  and  Hot'  l*art  I. 
Another  form  where  the  aii-  is  admitted  to  the  radiator  through  the 
wall  insteail(»f  the  lloor  is  shown  in  Vhj-.  23.    Fi<r.  24  shows  the  wall 


VALV£\ 


HEATER 


^=^ 


CASING 


SUPRLy 


DRIP 


WATER  L//VE 


%=D 


Q 


A/fA//V     RETURN 


Fi<:.  'i-l. 


box  with  louvre  shits,  and  netting,  through  wliicli  the  air  is  diawii. 
A  damper  door  is  placed  at  either  end  of  tlie  ladiator  base,  and  if 
desired,  when  the  cold  air  supply  is  shut  off  l^y  means  of  the 
register  in  the  air  duct,  the  radiator  can  be  converted  into  the 
ordinary  type  Vjy  opening  both  damper  doors,  thus  taking  the  air 
from  the  room  instead  of  from  the  outside.  It  is  customary  to 
increase  the  size  of  a  direct-indirect  radiator  30  per  cent,  above 
that  called  for  in  the  case  of  direct'  heating. 


HEATING  AND  VENTILATION. 


21 


TABLE  II. 


Square  Feet  of  Indirect  Radiation  which  will  be  Supplied  with 

Size  of 

Pipe. 

1 

I  Pound  Drop  in  200  Feet. 

J  Pound  Drop  in  100  Feet. 

^  Pound  Drop  in  100  Feet. 

1 

28 

40 

57 

11 

51 

72 

105 

4 

67 

95 

170 

2' 

185 

262 

375 

n 

835 

475 

675 

3 

540 

775 

1105 

H 

812 

1160 

1645 

4' 

1140 

1625 

2310 

5 

2030 

2900 

4110 

6 

3260 

4660 

6600 

7 

4830 

6900 

9810 

8 

6800 

9720 

13860 

CARE  AND  nANAQEMENT  OF   STEAM  HEATING  BOILERS. 

Special  directions  are  usually  supplied  by  the  maker  for  each 
kind  of  boiler,  or  for  those  which  are  to  be  managed  in  any 
peculiar  way.  The  following  general  directions  apply  to  all 
makes,  and  may  be  used  regardless  of  the  type  of  boiler  em- 
ployed. 

Before  starting  the  fire  see  that  the  boiler  contains  sufficient 
water.  The  water  line  should  be  at  about  the  center  of  the 
gage  glass. 

The  smoke  pipe  and  chimney  flue  should  be  clean  and  the 
draft  good. 

Build  the  fire  in  the  usual  way,  using  a  quality  of  coal 
which  is  best  adapted  to  the  heater.  In  operating  the  fire  keep 
the  iire-pot  full  of  coal  and  shake  down  and  remove  all  ashes  and 
cinders  as  often  as  the  state  of  the  fire  requires  it. 

Hot  ashes  or  cinders  must  not  be  allowed  to  remain  in  the 
ash  pit  under  the  grate  bars  but  must  be  removed  at  regular  in- 
tervals to  prevent  l)urning  out  the  grate. 

To  control  the  fire  see  that  the  damper  regulator  is  properly 
attached  to  the  draft  doors,  and  the  damper ;  then  regulate  the 
draft  by  weighting  the  automatic    lever  as  may  be  required   to 


22 


llKATINc;    AND  \' K\  TILATIOX. 


obtain  tlu"  lu'i'ossarv  steam  ])rt'.ssuri'  for  \val•lllill:^^  Should  tl'o 
water  ill  tlio  IxiiliM'  eseape  by  nieaiis  of  a  l)rokcii  fao-o  t^lass  or 
fi-oin  any  t>tlu'r  i-ause,  the  lire  should  Ih>  dumped,  and  the  boiler 
allowetl  to  eool  before  adding'  cold  wati'r. 

An  empty  boiler  should   never  be  idled   when  hot.     If  the 
water  gets    low    at  any  time,  but  still  shows  in  the  gage  ghuss, 

more  water  should  be  added 
hy  the  means  proviih'd  for  this 
purpose. 

The  safet}'  valve  should  be 
lifted  occasionally  to  see  that 
it  is  in  working  order. 

]f  the  boiler  is  used  in 
connection  with  a  gravity  system 
it  should  be  cleaned  each  year 
by  filling  with  pure  water  and 
em[)tying  through  the  blow-off. 
If  it  should  become  foul  or 
dirty  it  can  ])e  thoroughly 
cleansed  by  adding  a  few 
pounds  of  caustic  soda  and 
allowing  it  to  stand  for  a  day 
and  then  emptying  and  thor- 
oughly rinsing. 

During  the  summer  months 
it  is  recommended  that  the 
water  l)e  drawn  off  from  the  system,  and  that  air  valves  and 
safety  valves  be  opened  to  permit  the  heater  to  dry  out  and  to 
remain  so. 

Good  results  are  however  obtained  by  filling  the  heater  full 
of  water,  driving  off  the  air  by  boiling  slowly,  and  allowing  it 
to  remain  in  this  condition  until  needed  in  the  fall.  The  water 
should  then  be  drawn  off  and  fresh  water  added. 

The  heating  surface  of  the  boiler  should  be  kept  clean  and 
free  from  ashes  and  soot  by  means  of  a  brush  made  especially  for 
this  purpose. 

Should  any  of  the  rooms  fail  to  heat,  examine  the  steam 
valves  at  the  radiators.     If    a  two-pipe    system    both    valves    at 


Fig.  23. 


HEATING  AND  VENTILATION.  2S 

each  radiator  must  be  opened  or  closed  at  the  same  time  as  re- 
quired.    See  that  the  air  valves  are  in  working  condition. 

If  the  building  is  to  be  unoccupied  in  cold  weather  draw 
all  the  water  out  of  the  system  by  opening  the  blow-off  pipe  at 
the  boiler  and  all  steam  and  air  valves  at  the  radiators. 

HOT  WATER  HEATERS, 
Types.  Hot  water  heaters  differ  from  steam  boilers  principally 
in  the  omission  of  the  reservoir  or  space  for  steam  above  the  heat- 
ing surface.  The  steam  boiler  might  answer  as  a  heater  for  hot 
water,  but  the  large  capacity  left  for  the  steam  would  tend  to 
make  its  operation  slow  and  rather  unsatisfactory,  although  the 


Fig.  24. 

same  type  of  boiler  is  sometimes  used  for  both  steam  and  hot 
water.  The  passages  in  a  hot  water  heater  need  not  extend  so 
directly  from  bottom  to  top  as  in  a  steam  boiler,  since  the  problem 
of  providing  for  the  free  liberation  of  the  steam  bubbles  does  not 
have  to  be  considered.  In  general,  the  heat  from  the  furnace 
should  strike  the  surfaces  in  such  a  manner  as  to  increase  the 
natural  circulation  ;  this  may  be  accomplished  to  a  certain  extent 
by  arranging  the  heating  surface  so  that  a  large  proportion  of  the 
direct  heat  will  be  absorbed  near  the  top  of  the  heater.  Practi- 
cally the  boilers  for  low-pressure  steam  and  for  hot  water  differ 
from  each  other  very  little  as  to  the  character  of  the  heating-sur- 
face, so  that  the  methods  already  given  for  computing  the  size  of 
grate  surface,  horsepower,  etc.,  under  the  head  of  steam  boilers 
can  be  used  with  satisfactory  results  in  the  case  of  hot  water 
heaters.  It  is  sometimes  stated  tluit  owing  to  the  greater  differ- 
ence in  temperature  between  the  furnace  gases  and  tlie  water  in  a 
hot  water  heater,  as  compared  witli  steam,  that  the  heating  sur- 
face will  be  more  efficient  and  that  a  smaller  heater  can  be  used ; 


24 


HEATINc;  AND  VKNTILATION". 


wliilo  tins  is  triu>  lo  a  I'l'vtaiii  I'xlciit  (litl'cic'ut  aiitliDi itii's  at^ree 
that  this  advantage  is  so  small  tliat  no  arcduiit  should  he  taken  of 
it,  and  tlu'  <jjenoi'al  propoi'tions  of  llu'  lieatcr  should  he  ealoulated 
in  the  same  maimer  as  for  steam.  Fi<j^.  -•')  sliows  a  form  of  hot- 
water  healer  made  up  of  slahs  or  sec-tions  similar  to  the  sectional 
steam  lH>iler  shown  in  Part  I  ;  the  size  can  he  increased  in  tlie 
same  way  hy  adding  more  slahs.  A  dilferent  form  is  shown  in 
Fill.  -t).     This  is  made  of  cast  iron  but  is  not  a  sectional  boiler. 


Fij 


25, 


It  lias  no  horizontal  flues  for  the  ashes  and  soot  to  collect  in  and 
a  greater  i>art  of  the  heating  surfac«^  is  dire(;tly  exposed  to  the 
hottest  i)art  of  the  fire.  Fig.  27  shows  another  form  of  heater 
similar  in  jmnciple  to  tlie  one  just  described.  The  space  between 
the  outer  and  inner  sliells  surrounding  the  furnace  is  Idled  with 
water  and  also  the  cross  pipes  directly  over  the  fire  and  the  drum 
at  the  top.  The  supply  to  the  radiators  is  taken  off  from  the  top 
of  the  heater  and  the  return  connects  at  the  lowest  point. 

The    ordinary'    horizontal  and  vertical  tubular    boilers  with 
various  modifications  are  used  to  (piite  an   extent  for  hot  water 


HEATING  AND  VENTILATION. 


25 


heating  and  are   well  adapted  to  this  class  of  work,  especially  in 
the  case  of  large  buildings. 

Antoniatic  regulators  are  often  used  for  the  purpose  of  main- 


Fig.  26. 


taining  a  constant  temperature  of  tlu;  water.  They  are  constructed 
in  different  ways — some  depend  upon  the  expansion  of  a  metal 
pipe  or  rod  at  different  temperatures,  and  others  upon  the  vapor- 


26 


HKATING  AND  VKNTILATION. 


i/.iliim  and  ri)iisr(|iifiil  [ircssuit'of  i't>rt:iin  volatile  lic^uids.  Tliesc 
iiu'aiis  ait'  usiiallv  tMuploxcd  to  open  small  \alvt'.s  which  admit 
water  pressure  under  luhhi-r  diaphra^nis,  and  these  in  turn  are 
eouueeted  by  means  of  ehaiiis  with  the  draft  doors  of  the  furnace, 
ami  s«i  iv'jculate  the  draft  as  itMpiireil  to  uiaintain  an  even  temper- 
ature of  the  water  in  the  heater.  V'lg.  'iS  sliow.s  one  of  the  first 
l<ind.  •'  A  "  is  a  metal  rod  placi'd  iu  the  th)\v  pipe  from  the  heater, 
and  is  so  connected  with  the  valve   ^'li''   that  when  the  water 


Fi^'.  27. 


reaches  a  certain  temperature  the;  expansion  of  the  rod  opens  the 
valve  and  admits  water  from  the  street  pressure  through  the  pipes 
"  C  "  and  "  D  "  into  the  chamlx-r  "  E."  Tlie  l)ottom  of  "  E  "  consists 
of  a  lublxT  diaphraf,nii  whicli  is  forced  down  by  the  water  pressure 
and  carries  with  it  the  lever  which  o[)erates  the  dampers  as 
shown,  and  checks  the  fire.  When  the;  temjjeiature  of  the  water 
drops,  the  rod  contracts  and  valve  *'13"  closes,  shutting  off  the 


HEATING  AND  VENTILATION. 


27 


t ~" 


pressure  from  the  chamber  "  E."  A  spring  is  provided  to  throw 
the  lever  back  to  its  original  position  and  the  water  above  the 
diaphragm  is  forced  out  tlirough  the  pet  cock  "  G  "  which  is  kept 
slightly  open  all  of  the  time. 

DIRECT  HOT  WATER  HEATING. 

A  hot  water  system  is  similar  in  construction  and  operation 
to  one  designed  for  steam,  except  the  hot  water  flows  thiough  the 
pipes,  giving  up  its  heat  by  conduction  to  the  coils  and  radiators, 
which  in  turn  transfer  it  to  the  air  of  the  room  by  conduction 

and  radiation. 

The    flow    through    the    system    is    produced    solely  by  the 

difference  in  weight  of  the 
water  in  the  supply  and 
return  pipes,  due  to  the 
difference  in  temperature. 
When  water  is  heated  it 
expands,  and  thus  a  given 
voluiue  becomes  lighter 
and  tends  to  rise,  and  the 
cooler  water  flows  in  to 
take  its  place  ;  if  the  appli- 
cation of  heat  is  kept  up 
the  circulation  thus  pro- 
duced is  continuons.  The 
velocity  of  flow  depends 
upon  the  difference  in 
temperature  between  the 
supply  and  return,  and 
the  height  of  radiator 
above  the  boiler.  The 
horizontal  distance  of 
the  radiator  from  the  boiler  is  also  an  important  factor. 
Types  of  Radiating  Surface.  Cast  iron  radiators  and  circu- 
lation coils  are  used  for  hot  water  as  well  as  for  steam.  Hot 
water  radiators  differ  from  steam  radiators  principally  in  having 
a  horizontal  passage  at  tlie  top  as  well  as  at  the  bottom.  This 
construction  is   necessaiy  in  order   to   draw  off   the   air   which 


Fig.  28. 


28 


III.AI'INC    AM)   \K.\'riI, ATION. 


iXatluMs  al    llu'   top  of    v:u\i 
llu'  saiiu'  as  sloain    lailiaiois. 


•£ 


n 


u 


0 


v! 


top  or  scciidii.      ( )tlii'r\\  isc   tlii-y  are 

iiid   arc  well    a(la[)tc(l    tor    the   cnvii- 

lalioii  ol"  steam,  aiul  in  some 

respects   are   superior  to   the 

ordinary  j)attern, 

riic  t'onu  sliown  in  Fig. 
l^!>  is  made  with  an  opening 
at  tlie  top  for  the  entrance 
of  water  and  at  the  lK)ttom 
for  its  diseliarge,  thus  insur- 
ing a  supply  of  hot  water  at 
the  top  and  of  colder  water 
at  the  bottom. 

Some  hot  water  radiators 
are  made  with  a  cross-partition 
so  arranged  that  all  water  entering  passes  at  once  to  the  top,  from 
which  it  may  take  any  passage  toward  tlie  outlet.  Fig.  30  is  the 
more    common  form  of    radiator,  and    is    made   with    continuous 


Fig.  2i». 


Fig.  30. 


j;.i>hHgf.>,  at  lop  and  botU)m  ;  the  hot  water  is  supplied  at  one 
.side  and  drawn  off  at  the  other.  The  action  of  gravity  is  de- 
pended upon  for  making  the  hot  and  lighter  water  pass  to  the 


HEATING  AND  VENTILATION. 


29 


o 


top,  and  the  colder  water  sink  to  tlie  bottom  and  flow  off  through 
the  return.  Hot  water  radiators  are  usually  tapped  and  plugged 
so  that  the  pipe  connections  can  be  made  either  at  the  top  or  at 
the  bottom.     This  is  shown  in  Fig.  31. 

Efficiency  of  Radiators.  The  efficiency  of  a  hot  water  radia- 
tor depends  entirely  upon  the  temperature  at 
which  the  water  is  circulated.  The  best  practical 
results  are  obtained  with  the  water  leaving  the 
boiler  at  a  maximum  temperature  of  about  180 
degrees  in  zero  weather  and  returning  at  about 
160  degrees  ;  this  gives  an  average  temperature  of 
170  in  the  radiators.  Variations  may  be  made 
however  to  suit  the  existing  conditions  of  outside 
temperature.  We  have  seen  that  an  average  cast 
iron  radiator  gives  off  about  1.5  B.  T.  U.  per  hour 
per  square  foot  of  surface  per  degree  difference  in 
temperature  between  the  surrounding  air  and  the 
radiator,  when  working  under  ordinary  conditions, 
and  this  holds  true  whether  filled  with  steam  or 
water. 

If  we  assume  an  average  temperature  of  170 
degrees  for  the  radiators  then  the  difference  will  be  170  —  70  :^ 
100    degrees,    and    this  multiplied  by  1.5  =  150  which  may   be 
taken  as  the  efficiency  of  a  hot  water  radiator  under  the  above 
conditions,  which  represent  good  avei'age  practice. 

This  calls  for  a  water  radiator  about  1.5  times  as  large  as  a 
steam  radiator  to  heat  a  given  room  under  the  same  conditions. 
This  is  common  practice  although  some  engineers  multiply  by  the 
factor  1.6  which  allows  for  a  lower  temperature  of  the  water. 
Water  leaving,  the  boiler  at  170  degrees  should  return  at  about 
150  ;  tlie  drop  in  temperature  should  not  ordinarily  exceed  20 
degrees. 

System  of  Piping.  A  system  of  hot  water  heating  should 
produce  a  perfect  circulation  of  water  from  the  heater  to  the  radiat- 
ing surface,  and  thence  back  to  the  heater  through  the  returns. 
The  system  of  pi[)ing  usually  (Muploycd  for  liot  water  heating  is 
shown  in  Fig.  32  In  tliis  ai'rangement  the  main  and  branches 
have   an    inclination    upward  from  the    heater;  the    returns    are 


ri<r.  31. 


lIKATINt;    AND   \' KXIM  I.  ATIOX 


panillol  to  the  inj\iiis  and  havo  an  inclination  downward  toward 
tho  luNitor,  and  conncH't  with  it  at  tho  lowest  j)oint.  The  ilow 
pipes  or  risei's  are  taken  tVoin  iht-  tups  of  the  mains  and  may 
supply  one  or  more  radiatoi-s  as  retpiired.  The  ri'tiirn  risers  or 
drops  are  connected  with  the  return  mains  in  a  similar  manner. 
In  this  system  great  care  must  be  taken  to  pioduee  a  lu'arly  e([ual 
resistance  to  tlow  in  all  of  the  branches  so  that  each  radiator  may 
receive  its  full  siip[)ly  of  water.  It  will  always  be  fonnd  that  the 
princijial  current  of  heated  water  will  take  the  path  of  least  resis- 
tance, and  that  a  small  obstruction  or  irregularity  in  tiie  piping  is 


Fig.  32. 

sufficient  to  interfere  greatly  with  the  amount  of  heat  received  in 
the  different  parts  of  the  same  system. 

Expansion  Tank.  Every  system  for  hot  water  heating 
should  be  connected  with  an  expansion  tank  jilaced  at  a  point 
somewhat  al>ove  the  highest  radiator.  The  tank  must  in  every 
case  be  connected  to  a  line  of  piping  which  cannot  by  any  possible 
means  l>e  shut  off  from  the  boiler.  When  water  is  heated,  it 
expands  a  certain  amount,  depending  upon  tlie  temperature  to 
which  it  is  raised  and  a  tank  or  reservoir  should  always  be  j)ro- 
vided  to  care  for  this  increase  in  volume. 

Expansion  tanks  are  usually  made  of  heavy  galvanized  iron 


HEATING  AND  VENTILATION. 


31 


of  one  of  the  forms  shown  in  Figs.  33 
used  where  the  head  room  is  limited, 
heating  system  enters  the  bot- 
tom of  the  tank  and  an  open 
vent  pipe  is  taken  from  tlie  top. 
An  overflow  connected  with  a 
sink  or  drain  pipe  should  be 
provided.  Connections  should 
be  made  with  the  water  supply 
both  at  the  boiler  and  at  the 
expansion  tank,  the  former  to 
be  used  when  first  filling  the 
system,  as  by  this  means  all  air 
is  driven  from  the  bottom  up- 
ward and  is  discharged  through 
the  vent  at  the  expansion  tank. 
Water  that  is  added  afterward 


and  34,  the  latter  being 
The  connection  from  the 


oy£fiirco\A/ 


CONMCCTION 


Fig.  33. 


may  be  supplied  directly  to  the  expansion  tank  where  the  water 
line  can  be  noted  in  the  gage  glass.  A  ball  cock  is  often  arranged 
to  keep  the  water  line  in  the  tank  at  a  constant  level. 


vcNT  Pipe: 


oveRrLOv\r 


Fig.  34. 


The  size  of  the'  expansion  tank  depends  upon  the  volume  of 
water  contained  in  the  system,  and  the  temperature  to  which  it  is 
heated.  The  following  rule  for  computing  the  capacity  of  the 
tank  may  be  used  with  satisfactory  results. 

The  square  feet  of  radiation  divided  by  40  equals  the  required 
capacity  of  the  tank  in  gallons. 


lIl'.A'riNC    AM)    \  KNI'lLAI'ION 


Overhead  Distribution.  Tliis  systfin  nf  piping  is  shown  in 
Fig.  ^>").  A  singlo  riser  is  carried  dircetlv  l<>  I  lie  exjiansion  tank, 
from  whiih  hranolies  are  taken  to  sii|)|ilv  tlie  varions  drops  lo 
wliieli  tlie  radiators  are  eonneeted.  An  inijtortaiit,  advantage  in 
eonneetion  with  this  system  is  that  the  air  lisi's  at  once  to  the 
expansion  taidc  and  escapes  throtigli  the  vent,  so  that  air  valves 
are  not  reipiired  on  (he  radiators. 


EXPANS/ON    TANK 


*- • 

^ 

_ _ ^v 

L^       __ 

S£VO/VD  FLO  OP 

-« 

■.y  ,-y ,                 '■','■- 

^^^^^^^^ 

^^^^ 

msi. 

hi- 

/-,- 

-« 

■^^ 

'"^Mf/j^Mii^y^m^A 

'^^'^;mM)mmm^^mff^;f^my. 

'^^m 

1 

H£AT£H 

Fig.  85. 


Pipe  Connections.  Tliere  are  various  methods  of  connecl>- 
ing  the  radiators  with  tlie  mains  and  risers.  P^ig.  36  shows  a 
i-adiator  connected  witli  the  liriri/ontal  flow  and  return  mains 
wliicli  are  located  lielow  the  lloor.  The  manner  of  connecting 
wiili  a  verticil  )-iser  and  return  droj)  is  sliown  in  Fig.  .'57.  As  tlie 
water  tends  to  flow  to  the  highest  point,  the  radiators  on  the  lower 
floors  should  be  favored  b}'  making  the  connection  at  the  top  of 
the  riser  and  taking  the  pipe  for  the  uppei-  lloois  from  tlx^  side  as 
shown.  Fig.  38  illustrates  the  manner  of  connecting  with  a 
radiator  on  an  upper  floor  Avliere  the  supply  is  connected  at  the 
top  of  the  radiat<^ir. 


HEATING  AND  VENTILATION. 


8S 


The  connections  shown  in  Figs.  89  and  40  are  used  with  the 
overhead  system  shown  in  Fig.  35. 

Where  the  connection  is  of  the  form  sliown  at  the  left  in 
Fig.  35,  the  cooler  water  from  the  radiitors  is  discharged  into  the 
supply  i)ipe  again  so  that  the  water  furnished  to  the  radiator^  on 


Fig.  36. 


Fig.  37. 


the  lower  floors  is  at  a  lower  temperature,  and  the  amount  of  heat- ' 
ing  surface  must  be  correspondingly  increased  to  make  up  for  this 
loss. 

For    example. — If    in    the  case  of  Fig.   35    we  assume    the 
water  to  leave  the  heater  at  180  degrees  and  return  at  160   we 


Fig.  38. 


Fig.  39. 


shall  iiave  a  diop  in  temperature  of  10  degrees  on  each  floor, 
that  is,  the  water  will  enter  the  radiator  oa  the  second  floor  at 
180  degi-ees  and  leave  it  at  170  and  will  enter  the  radiator  on  the 
first  floor  at  170  and  leave  it  at  160.  The  average  temperatures 
will  be  175  and    165  respectively.     The    efficiency  in    the   fiist 


;54 


IIEATINc;   AM)   VKN'IMI.VriON". 


rsii>o  will  Ini  17.")  —  70  =  lOoiiiul  10')  X  ^''^>  =  l'")7.  In  the  sih'oikI 
case  U)')  —  70:=  95  juul  05  X  1.5  =  142,  so  that  tin-  nuliiitor  on 
tlu'  tirst  lloor  will  liavo  to  bo  LugiT  tlian  tluit  on  llic  second  floor 
in  ihe  ratio  of  157  to  142,  in  order  to  do  the  same  work. 

Where  the  radiators  discharge  into  a  separate  letnrn  as  in 
the  case  of   Fig.  32  or  those  at  the  right  in   Fig.   35,  we  may  as- 
sume the  temperature  of   the   water 
to  he  the  same  on  all  iloors  and  irive 
the  radiators  an  eijual  (illiciency. 

In  a  dwelling  house  of  two 
stoiies  no  difference  wouhl  be  made 
in  the  sizes  of  radiatore  on  the  two 
Iloors,  but  in  the  case  of  a  tall  office 
Ituilding  corrections  would  neces- 
saril}-  be  made  as  described. 

Where  circulation  coils  are  used 
they  should  be  of  a  form  which  will  tend  to  produce  a  flow  of 
water  through  them.  Figs.  41,  42  and  43  show  different  ways  of 
making  up  and  connecting  these  coils.  In  Figs.  41  and  43  the 
supply  pipes  may  be   either  drops  or   risers,  and  in  the    latter 


Fig.  40. 


"^ 


^ 


P 


P 


Fig.  41. 


case  the  return  in  Fig.  43  may  l)e  carried  Iwck  if  desired  into  the 
supply  drop  as  shown  by  the  dotted  lines. 

Combination  Systems.  Sometimes  the  boiler  and  piping 
are  airanged  for  either  steam  or  hot  water,  since  the  demand  for  a 
higher  or  lower  temperature  of  the  radiators  might  change. 

The  object  of  this  arrangement  is  to  secure  the  advantages 


HEATING  AND  VENTILATION. 


35. 


of  a  hot  water  system  for  moderate  temperatures,   and   of  steam 
heating  for  extremely  cold  weather. 

As  less  radiating  surface  is  required  for  steam  heating,  there 
is  an  advantage  due  to  the  reduction  in  first  cost.     This  is  of  con- 


Fis.  42. 


siderable  importance,  as  a  heating  system  must  be   designed  of 
such  dimensions  as  to  be   capable  of  warming   a   building  in  the 


Fiff.  43. 


coldest  weather,  and  this  involves  the  expenditure  of  a  consider- 
able amount  for  radiating  surfaces,  which  are  needed  only  at  rare 
intervals.  A  combination  system  of  liot  water  and  steam  heating 
requires,  first,  a  heater  or  boiler  which  will  answer  for  either  pur- 


86 


IIKATINC    AND   V I'.N'PI L ATIOX. 


posi' ;  M'loiul,  a  syst<»m  of  pipiii!:,'  which  will  pfniiit  the  ^'in-uhition 
of  either  steam  or  hot  \v:\hM-.  and  third,  the  nsi>  of  radiators  which 
are  adapted  to  hoth  kinds  of  heating,'.  These  re(iiiirenients  will  be 
met  hy  iisini,^  a  st(>am  boiler  provided  with  all  the  fittings  required 
for  steam  heating,  but  so  arranged  that  the  damper  regulator  may 


Fig.  44. 


Fig.  4.^, 


be  closed  by  means  of  valves  when  the  system  is  to  be  used  for 
hot  water  heating.  The  addition  of  an  expansion  tank  is  re- 
quired, which  must  be  so  arranged  that  it  can  be  shut  off  when 
the  system  is  used  for  steam  heating.     The    system  of  piping 

shown  in  Fig.  32  is  best  adapted 
for  a  combination  system,  altliough 
an  overhead  distribution  as  shown 
in  P'ig.  35  may  be  used,  by  shut- 
ting off  the  vent  and  overflow 
pipes,  and  placing  air  valves  on 
the  radiators. 

AVliile  this  system  has  many 
advantages  in  the  way  of  cost 
over  the  complete  hot  water  system,  yet  the  labor  of  changing 
from  steam  to  hot  water  will  in  .some  cases  be  troublesome,  and 
sliould  the  connections  to  the  expansion  tank  not  be  opened, 
serious  results  would  follow. 

Valves  and   Fittings.     Gate  valves  .should  always  be  u.sed 
in  connection  with  hot  water  piping,  although  angle  valves  may 


Fig.  40. 


HEATING  AND  VENTILATION. 


37 


be  used  at  the  radiators.  There  are  several  patterns  of  radiator 
valves  made  especially  for  hot  water  work  ;  their  chief  advantage 
lies  in  a  device  for  quick  closing,  usually  a  quarter  or  half  turn 
being  sufficient  to  open  or  close  the  valve.  Two  different  designs 
are  shown  in  Figs.  44  and  45. 

It  is  customary  to  place  a  valve  in  only  one  connection  as 
that  is  sufficient  to  stop  the  flow  of  water  through  the  radiator; 
a  fitting  known  as  a  "union  elbow"  is  often  employed  in  place  of 
the  second  valve.      (See  Fig.  46.) 

Air  Valves.  The  ordinary  pet-cock  air  valve  is  the  most  re- 
liable for  hot-water  radiators,  although  there  are  several  forms  of 
automatic  valves  which  are  claimed 
to  give  satisfaction.  One  of  these 
is  shown  in  Fig.  47.  This  is  similar 
in  construction  to  a  steam  trap.  As 
air  collects  in  the  chamber,  and  the 
water  line  is  lowered,  the  float  drops, 
and  in  so  doing  opens  a  small  valve 
at  the  top  of  the  chamber  which 
allows  the  air  to  escape.  As  the 
water  flows  in  to  take  its  place  the 
float  is  forced  upward  and  the  valve 
is  closed. 

All  radiators  which  are  supplied 
by  risers  from  below  should  be  pro- 
vided with  air  valves  placed  in  the 
top  of  the  last  section  at  the  return  end.  If  they  are  supplied 
by  drops  from  an  overhead  system  the  air  will  be  discharged 
at  the  expansion  tank  and  air  valves  will  not  be  necessary  at  the 
radiators. 

Fittings.  All  fittings,  such  as  elbows,  tees,  etc.,  should  be  of 
the  "  long  turn  "  pattern.  If  the  common  form  is  used,  they 
should  be  a  size  larger  than  the  pipe,  bushed  down  to  the  proper 
size.     The  long  turn  fittings,  however,  are  preferable. 

Pipe  Sizes.  The  size  of  pipe  required  to  supply  any  given 
radiator  depends  upon  four  conditions  ;  first  the  size  of  the  radia- 
tor, second  its  elevation  above  the  boiler,  third  the  length  of  pipe 
recjuired  to  connect  it  with  the  boiler,  d^ndi  fourth  the  difference  in 


Fig.  47. 


38 


lIKATlNHi  AND  VENTILATION. 


tomponituiv    lu'twi'iMi    the    sii|>|ih'    and    ictmii.         I'ln'    following 
illustration  will  scivt*  tit  niakc  tlu'sc  j)oin(s  clear. 

If  we  shoultl  take  a  s^liuss  tube  of  the  form  shown  in  Fig.  48, 
till  it  with  water  and  holil  it  in  a  vertii'al  j)osition,  we  would  notice 
that  the  water  remained  perfectly  quiet ;  now  if  the  llanie  of  a  lamp 
were  held  near  the  tube  A  and  a  few  drops  of  coloring  matter  were 
poured  into  the  tube,  we  would  lind  that  the  water  was  in  motion, 
and  the  current  would  be  in  the  direction  showai  by  the  arrows. 
While  the  water  in  both  tubes  was  at  the  same  temperature,  the  two 
columns  were  of  the  same  weight  and  remained  in  equilibrium.  If, 
however,  the  water  in  cohnnn  A  is  heater,  it  ex[)ands  and  becomes 


eXPANS/ON    TA/^K 


RAO/ATOR 
Si 


Fig.  49. 


lighter  than  column  I>,  and  is  forced  upward  by  the  heavier  water 
falling  toward  the  bftttom  of  the  tube.  The  heated  water  flows 
across  the  top  and  into  I>  wdiere  it  takes  the  })lace  of  the  cooler 
water  which  is  settling  to  tlie  bottom.  As  long  as  there  is  a 
difference  in  the  temperature  of  the  two  columns  this  action  will 
continue.  If  now  we  replace  the  lamp  by  a  furnace,  and  connect 
the  two  columns  A  and  B  at  the  top  by  inserting  a  radiator,  we 


HEATING  AND  VENTILATION. 


39 


shall  have  the  same  illustration   in   practical  form  as   utilized  in 
hot  water  heating.     (See  Fig.  49). 

The  heat  given  off  by  the  radiator  always  insures  a  differ- 
ence in  temperature  between  the  columns  of  water  in  the  supply 
and  return  pipes,  so  that  as  long  as  heat  is  supplied  by  the  furnace 
the  flow  of  water  will  continue.  The  greater  the  difference  in 
temperature  of  the  water  in  the  two  pipes,  the  greater  the 
difference  in  weight,  and  consequently  the  faster  the  flow.  The 
greater  the  height  of  the  radiator  above  the  heater  the  more  rapid 
the  flow,  for  the  difference  in  weight  between  two  columns  1  foot 
high  and  two  columns  10  feet  high  is  ten  times  as  great  and  if 
there  were  no  friction  in  the  pipes  the  flow  would  be  directly 
proportional  to  the  elevation  of  the  radiator  above  the  heater. 
The  quantity  of  water  discharged  by  a  given  pipe  under  constant 
pressure  varies  inversely  as  the  length  of  pipe  ;  that  is,  if  a  pipe 
100  feet  long  will  discharge  10  gallons  per  minute  under  a  given' 
pressure,  it  will  discharge  only  half  as  many  gallons  if  the  length 
is  increased  to  200  feet,  the  pressure  remaining  the  same. 

As  it  would  be  a  long  process  to  work  out  the  required  size 
of  each  pipe  for  a  heating  system,  the  following  tables  have 
been  prepared,  covering  the  usual  conditions  to  be  met  with  in 
practice. 

Table  III  gives  the  number  of  square  feet  of  direct  radia- 
tion which  different  sizes  of  mains  will  supply  for  varying  lengths 
of  run. 


TABLE  III. 


Square  Feet  of  Radiating  Su 

rface. 

Size  of  Pipe. 

100  ft. 
Run. 

200  ft. 
Run 

300  ft. 
Run. 

50 
125 
200 
300 
450 
700 
1150 

400  ft. 
Run. 

500  ft. 
Run. 

600  ft. 
Run. 

700  ft. 
Run. 

890  ft. 
Run. 

1000  ft. 
Run. 

1 
IX 

2 

2K 
3 

4 
5 
6 

7 

30 
60 
100 
200 
360 
550 
850 
1200 

50 

75 
150 
250 
400 
600 
850 
1400 

100 
175 
275 
400 
600 
1000 
1600 

75 
150 
250 
350 
525 
700 
1400 

125 
225 
325 
475 
850 
13U0 

200 
300 
450 
775 
1200 
1706 

175 

250 

400 

725 

1150 

1600 

150 
225 
350 
650 
1000 
1500 

40  IIKATIXG  AND   \' FATILAl'K^X. 


These  qiumtities  have  been  cjilcuhit<'<l  nu  a  Itasis  of  10  feet 
diiYorenoe  in  ohn'atioii  hetweeu  the  center  of  the  healer  ami  tlie 
r.viiatoi-s,  and  a  dilVereiiee  In  lein[)eralure  of  17  th'trrees  between 
the  su{>]>ly  anil  relnrn.  " 

This  table  may  be  nsed  for  all  hori/.oiital  mains.  l'\)r  the 
vertical  risei-s  or  ilrops,  table  I  \'  may  he  nsed.  'I'his  has  been 
conipnteil  for  the  same  (liffeiiMice  in  temperature,  and  t»ives  the 
square  feet  of  surface  which  dilTerent  sizes  of  pipe  will  supply 
on  the  different  lloors  of  a  biiihlin!^,  assuming  the  height  of  the 
stories  to  be  10  ft-ct.  Where  a  single  riser  is  carried  to  the  top 
of  a  building  to  supply  the  radiators  on  the  floors  below,  by  drop 
pipes,  we  must  first  get  what  is  called  the  "  average  elevation  of 
the  system"  before  taking  its  size  from  the  table.  This  may  be 
illustrated  by  the  following  diagram,  (see  Fig.  50). 

In  A  we  have  a  riser  carried  to  the  third  story  and  from  there  a 
drop  brought  down  to  supply  a  radiator  on  the  first  floor.  The 
elevation  available  for  producing  a  flow  in  the  riser  is  only  10  feet, 
the  same  as  though  it  extended  only  to  the  radiator.  The  water 
in  the  two  pipes  above  the  radiator  is  practically  at  tbe  same 
temperature  and  therefore  in  equilibrium,  and  lias  no  effect  on  the 
flow  of  the  water  in  the  riser.  (Actually  there  would  be  some 
radiation  from  the  pipes,  and  the  return,  above  the  radiator,  would 
be  slightly  cooler,  but  for  purposes  of  illustration  this  may  be 
neglected).  If  the  radiator  was  on  the  second  (loor  the  elevation 
of  the  system  would  be  20  feet  (see  B),  and  on  the  third  floor  30 
feet,  and  so  on.  The  distance  which  the  pipe  is  carried  above  the 
first  radiator  which  it  supplies  has  but  little  effect  in  producing  a 
flow,  especially  if  covered,  as  it  should  be  in  practice.  Having 
seen  that  the  flow  in  the  main  riser  depends  upon  the  elevation  of 
the  radiators,  it  is  easy  to  see  that  the  way  in  which  it  is  distri- 
buted on  the  different  floors  must  be  considered.  For  example, 
in  H,  Fig.  50,  there  will  be  a  more  rapid  flow  through  the  riser 
with  the  radiators  as  shown  than  there  would  be  if  they  were 
reversed  and  the  larger  one  were  placed  upon  the  first  floor. 

We  get  the  average  elevation  of  the  system  by  nudtiplying 
the  square  feet  of  radiation  on  each  floor  by  the  elevation  above 
the  heater,  than  adding  these  products  together  and  dividing  the  same 


HEATING  AND  VENTILATION. 


41 


by  the  total  radiation  in  the  whole  system.     In  the  case  shown 
in  B  the  average  elevation  of  the  system  would  be 

(100  X  30)  +  (50  X  20)  +  go  X  25)  ^  26  +  feet, 
• foo+"50"+10 

and  we  must  proportion  the  main  riser  the   same  as  though  the 


Fig.  50. 


whole  radiation  were  on  the  second  floor.  Looking  m  table  IV 
we  find  for  the  second  story  that  a  1^  inch  pipe  will  supply  140 
square  feet  and  a  2  inch  pipe  275.     Probably  a  11  inch  pipe  would 

be  sufficient.  ■,    ^^J^ 

Although  the  height  of  the  stories  varies  in  different  buildings, 


-Ill 


IIKATIXU  AXn  \K\'riLATION. 


10  feet  will  l>i'  t'mind  sunicii'iitly  acciiratr  t'di-  oi-diiiary  practice. 

TABLE  IV. 


Siie  of 

Square  Feet  of  Radiating  Surface. 

Riser. 

Ist  story 

2d  Story 

3d  Story 

4th  Story 

5th  Story 

6th  Story 

1 

30 

55 

65 

75 

85 

95 

u 

60 

00 

110 

125 

140 

160 

ll 

100 

140 

165 

185 

210 

240 

2 

200 

215 

376 

425 

500 

H 

350 

475 

3 

550 

H 

850 

INDIRECT  HOT  WATER  HEATING. 

Types  of  Heaters.  The  heaters  for  indirect  hot  water  heat- 
ing are  oi  the  same  general  form  as  those  used  for  steam .  Tlie 
heatei-s  shown  in  Figs.  9,  14  and  15  of  Part  I,  are  common 
patterns.     The  "drum  pin,"  Fig.  14,  is  an  excellent  form,  as  the 

method  of  making  the 


Fiji.  51. 


connections  insures  a 
uniform  distribution  of 
water  througli  the  stack. 
Fig.  51  shows  a  sec- 
tion of  good  form  for 
water  circulation,  and 
also  of  good  depth,  which  is  a  necessary  point  in  the  design 
of  hot  water  heaters.  They  should  not  be  less  than  10  or  12 
inches  for  good  results.  Box  coils  of  the  form  given  for  steam 
may  also  be  used,  provided  the  connections  for  supply  and  return 
are  made  of  good  size. 

Size  of  Heaters.  As  indirect  hot  water  heaters  are  used 
principally  in  tln^  warming  of  dwelling  houses,  and  in  combination 
with  direct  radiation,  the  easiest  method  is  to  compute  the  surfaces 
required  for  direct  radiation  and  multiply  these  results  by  1.5  for 
pin  radiators  of  good  depth.     For  other  forms  the  factor  should 


HEATING  AND  VENTILATION.  43 


vary  from  1.5  to  2,  depending  upon  the  depth  and  proportion  of 
free  area  for  air  flow  between  the  sections. 

If  it  is  desired  to  calcuhite  the  required  surface  directly  by  the 
thermal  unit  method,  we  may  allow  an  efficiency  of  from  360  to 
380  for  good  types  in  zero  weather. 

Flues  and  Casings.  For  cleanliness,  as  well  as  for  obtaining 
the  best  results,  indirect  stacks  should  be  hung  at  one  side  of  the 
register  or  flue  receiving  the  warm  air,  and  the  cold-air  duct 
should  enter  beneath  the  heater  at  the  other  side.  A  space  of  1 0 
inclies,  and  preferably  12,  should  be  allowed  for  the  warm  air 
above  the  stack.  The  top  of  the  casing  should  pitch  upward 
toward  the  warm-air  outlet  at  least  an  inch  in  its  length.  A  space 
of  from  6  to  8  inches  should  be  allowed  for  cold  air  below  the 
stack. 

As  the  amount  of  air  warmed  per  square  foot  of  heating  sur- 
face is  less  than  in  the  case  of  steam,  we  may  make  the  flues 
somewhat  smaller  as  compared  with  the  size  of  heater.  The  fol- 
lowing proportions  may  be  used  under  usual  conditions:  1^  square 
inches  per  square  foot  of  radiation  for  the  first  floor,  and  1 J  square 
inches  for  the  second  floor,  and  1^  square  inches  for  the  cold-air 
duct. 

Pipe  Connections.  In  hot  water  indirect  work  it  is  not 
desirable  to  supply  more  than  80  to  100  square  feet  of  radiation 
from  a  single  connection.  Wlien  the  requirements  call  for  larger 
stacks  they  should  be  divided  into  two  or  more  groups  according 
to  the  size. 

The  branches  supplying  the  stacks  should  pitch  upward  from 
the  boiler  to  a  point  directly  over  the  stack,  then  drop  and  make 
connection  with  the  heater  at  such  a  point  as  the  special  form  in 
use  requires.  An  air  valve  should  be  placed  in  the  highest  point 
of  the  pipe  just  before  it  drops  to  the  heater.  The  return  should 
be  taken  from  the  bottom  of  the  stack  and  carried  at  a  lower 
level  back  to  the  boiler  or  heater. 

Conditions  may  make  it  necessary  to  bring  back  several 
separate  returns  to  the  heater,  but  it  is  better  practice  to  use 
one  large  flow  n)ain  and  a  single  return  of  the  same  size,  branch- 
ing to  the  different  stacks  as  necessary. 

Pipe  Sizes.      As    the    difference    in    elevation   between    the 


44  HEATING  AND  VENTILATION. 


stacks  and  tlio  lioalor  is  lu'i'i'ssarily  small,  tlu'  pipes  slioiiid  ho  of 
ample  size  to  otTsot  the  slow  vi'lotity  of  How  tlirou^li  tlicin.  The 
followiiicf  sizes  for  runs  nj)  to  lOd  feet  will  he  found  ample  for 
ordinary  conditions.  Sonie  eni^ineers  make  a  ])raetict'  of  nsinj^ 
somewhat  smaller  pipes,  hut  the  larger  sizes  will  in  general  he 
found  more  satisfactory. 

TABLE  V. 


Size  of  Pipe. 

Square  feet  uf  Indirect  Radiation. 

1 

15 

1] 

30 

ll 

50 

2" 

100 

oi 

200 

? 

300 

3.^> 

400 

4" 

GOO 

5 

1000 

CARE    AND    MANAGEMENT    OF    HOT   WATER    HEATERS. 

The  directions  given  for  the  care  of  steam  heating  boilers 
apply  in  a  general  way  to  hot  water  heaters  as  to  the  methods  of 
caring  for  the  fires  and  for  cleaning  and  filling  the  heater.  Only 
the  special  points  of  difference  need  be  considered.  Before  build- 
ino-  the  fire  all  the  pipes  and  radiators  must  be  full  of  water  and 
the  expansion  tank  should  be  partially  filled  as  indicated  by  the 
gage  glass.  Should  the  water  in  any  of  the  radiators  fail  to 
circulate,  see  that  the  valves  are  wide  open  and  that  the  radiator 
is  free  from  air.  Water  must  always  be  added  at  the  expansion 
tJink  when  for  any  reason  it  is  drawn  from  the  system. 

The  required  temperature  of  the  water  will  depend  upon  the 
outside  conditions  and  only  enough  fire  should  be  carried  to  keep 
the  rooHLS  comfortably  warm.  'Hiermometers  should  be  placed  in 
the  flow  ami  return  {)ipes  near  the  heater  as  a  guide.  Special 
forms  are  made  for  this  purpose  in  which  the  bulb  is  immersed  in 
a  bath  of  oil  or  mercury.     See  Fig.  52, 

EXHAUST  STEAM  HEATING. 

Steam  after  l>eing  used  in  an  engine  contains  the  greater  part 
of  its  heat,  and  if  not  condensed  or  used  for  other  purposes  it  can 


HEATING  AND  VENTILATION. 


45 


usually  be  employed  for  heating  without  affecting  to  any  great 
extent  the  power  of  the  engine. 

The  systems  of  steam  heating  which  have  been  described  are 
those  in  which  the  water  of    condensation  flows    back  into   the 
boiler  by  gravity;  where  exhaust  steam  is  used  the  pressure  is 
much  below  that  of  the  boiler  and 
it  must  be   returned   either  by   a 
pump  or  return  trap.     The  exliaust 
steam  is  often  insufficient  to  sup- 
ply the  entire  heating  system  and 
must    be    supplemented    by    live 
steam    taken     directly    from    the 
boiler.       This      must     first     pass 
through  a  reducing  valve  in  order 
to  reduce   the  pressure  to   corres- 
pond with  that  carried  in  the  heat- 
ing system. 

The  exhaust  steam  discharged 
from  non-condensing  engines  con- 
tains   from  20  to  30  per  cent  of 
water,    and    considerable     oil     or 
greasy  matter  which  has  been  em- 
ployed for  lubrication.     When  the 
engine  is  exhausting  into  the  air, 
the  pressure  in  the    exhaust  pipe 
is  but  slightly  above  that  due  to 
the    atmosphere.       The    effect    of 
passing    exhaust    steam     through 
the  pipes  and  radiators  of  a  heat- 
ing   system    is    likely    to    increase    the    back    pressure    on    the 
engine  and  reduce  its  effective  work ;  this  must  be  offset  by  rais- 
ino-  the  boiler  pressure  or  increasing  the  cut-off  of  the  engine. 

An  engine  does  not  deliver  steam  continuously  but  at  regular 
intervals  at  the  end  of  each  stroke  and  the  amount  is  likely  to 
vary  with  the  work  done  since  the  governor  is  adjusted  to  admit 
steam  in  such  a  quantity  as  is  required  to  maintain  a  uniform 
speed.  If  the  work  is  light,  very  little  steam  will  be  admitted  to 
the  engine  and  for  this  reason  the  supply  available  for  heating  nviy 


46 


lIEATIXCi  AXI)  ^'ENT1LATI0N. 


vary  soin»>\vliat  ilejiciuliiiL;'  ujioii  (lit>  use  inadr  of  (lie  |)(»\\'(>r  (1(>- 
livered  l)y  llu>  I'liLrinc.  In  mills  ihc  aiiKtunt  df  cxliaust  steam 
is  prai'tii-ally  constant  :  in  nHicc  buildings  where  jHiwiM'  is  used  tor 
lii::litintr,  tlie  variation  is  L;ii'aii'r,  especially  it"  power  is  also 
re(|nire(l  tor  the  running  ol'  cle\ators. 

The  general  requirements  for  a  successful  system  of  exhaust 
stoam  heating  include  a  system  of  piping  of  such  jjroportions 
that  onlv  a  slight  increase  in  hack  prcssiu'c  will  In;  thrown  u[)on 
the  engine;  a  connection  which  shall  autonialic-ally  supply  live 
steam  at  a  reduced  pressure  as  needed ;  j)rovision  for  removing  the 
oil    from    the    exhaust   steam ;   a    lelief  or   back    pressure    valve 

REOUCINE  ,  VALVE 


BY^PASS 

Fig.  5:^. 

arranged  to  prevent  any  sudden  increase  in  l)ack  pressure  on  the 
engine,  and  a  return  system  of  some  kind  for  returning  the  water 
of  condensation  back  to  the  boiler  against  a  higher  pressure. 
These  requirements  may  be  met  in  various  ways  depending  upon 
actual  conditions  found  in  different  cases. 

To  prevent  smldcn  changes  in  the  back  pressure  due  to 
irregular  supply  of  steam,  the  exhaust  pipe  from  the  engine  is 
often  carried  to  a  closed  tank  having  a  capacity  from  30  to  40 
times  that  of  the  engine  cylinder.  This  tank  may  be  provided 
with  baffle  plates  or  other  arrangements  and  serve  as  a  separator 
for  removing  the  oil  from  the  steam  as  it  passes  through. 

Any  system  of  piping  may  be  used  but  great  care  should  be 
taken  that  as  little  resistance  as  possible  is  introduced  at  bends 
and  fittings  ;  and  the  mains  and  blanches  should  be  of  ample  size. 
Usually  the  best  results  are  obtained  from  the  system  in  which 
the  main  steam  pipe  is  carried  directly  to  the  top  of  the  Ijiiilding, 
the  distributing  pipes  run  from  that  point,  and  the  radiating  sur- 
faces supplied  by  a  down-flowing  current  of  steam. 


HEATING  AND  VENTILATION. 


47 


Before  taking  up  the  matter  of  piping  in  detail  a  few  of  the 
more  important  pieces  of  apparatus  will  be  described  in  a  brief 
way. 

Reducing  Valves.  The  action  of  pressure  reducing  valves 
has  been  taken  up  quite  fully  in  "  Boiler  Accessories,"  and  need 
not  be  repeated  here.     When 


the  reduction  in  pressure  is 
large,  as  in  the  case  of  a  com- 
bined power  and  lieating 
plant,  the  valve  may  be  one 
or  two  sizes  smaller  than  the 
low  pressure  main  into  which 
it  discharges.  For  example 
• — a  5-inch  valve  will  supply 
an  8-inch  main,  a  4-inch  a 
6-inch  main,  a  3-inch  a  5-inch 
main,  a  21-inch  a  4-inch  main, 
etc. 

For  the  smaller  sizes  the 
difference  should  not  be  more 
than  one  size.  All  reducing 
valves  should  be  provided 
with  a  valved  by-pass  for 
cutting  out  the  valve  in  case 
of  repairs.  The  connection 
is  usually  made  as  shown  in 
plan  by  Fig.  53. 

Grease  Extractor.  As 
already  stated,  when  exhaust 
steam  is  used  for  heating  pur- 
poses, it  must  first  be  passed 

through  some  form  of  separator  for  removing  the  oil.  This  is 
usually  effected  by  introducing  a  series  of  baffling  plates  in  the 
path  of  the  steam ;  the  particles  of  oil  striking  these  are  stopped 
and  thus  separated  from  the  steam.  The  oil  drops  into  a  receiver 
provided  for  this  purpose  and  is  discharged  through  a  trap  to  the 
sewer. 

In  the  separator,  or  extractor,  shown  in  Fig.  54,  the  separa- 


DrSCHARGE: 
Fiff.  54. 


48 


1IKATI\(;   ANP   \K\'riI.ATIOK 


tion  is  accomplished  by  ft  series  of  plates  placed  in  a  vertical  posi- 
tion in  the  body  of  the  separator  throu<Th  which  the  steam  must 
pass.  These  plates  consist  nf  upiij^lit  liollow  columns,  witii 
openiui^s  at  re^j^iilar  intervals  lor  the  admission  of  water  and  oil, 
which  drains  downward  to  the  receiver  below.  The  steam  takes 
a  /.ig-zag  course  and  all  ol'  it  coiui's  in  contact  M'ith  the  intercept- 
ing plates,  which  insures  a  thorough  separation  of  the  oil  and 
other  solid  matter  from  the  steam.  Another  form,  shown  in  Fig. 
.'>n,  gives  excellent  results  and  has  the  advantage  of  providing 
an  etjualizing  chamber  for  overcoming,  to  some  extent,  the  une(|nal 
pressure  due  to  the  varying  load  on  the  engine.     It  consists  of  a 


LIVE  STEAM   h  — 
FROM  REDUCING 
\/ALV£ 


eXHAUST 
fflOM  £NG/N£ 


'N^W 


£Xt^£LSIOR  ,'SrRAIN'fR 


¥ 


\ 


Sr£AM  TO 

HEATING 

SYSTEM 


HANDHOLE 


Fig.  55. 


tank  or  receiver  about  4  feet  in  diameter,  with  heavy  boiler  iron 
lieads  slightly  crowned  to  give  stiffness.  'J'hrough  the  center  is  a 
layer  of  excelsior  (wooden  shavings  of  long  fibre)  about  12  inches 
in  thickness,  supported  on  an  iron  gi-ating,  with  a  similar  grating 
laid  over  the  top  to  hold  it  in  i)lace.  The  steam  enters  the  space 
]>elow  the  excelsior  and  passes  upward,  as  shown  by  the  arrows. 
The  oil  is  caught  by  the  excelsior  which  can  be  renewed  from 
time  to  time  as  it  becomes  saturated.  The  oil  and  water  which 
fall  to  the  bottom  of  the  receiver  are  carried  off  through  a  trap. 
Live  steam  may  l>e  admitted  through  a  reducing  valve  for  supple- 
menting the  exhaust  when  necessary. 

Back  Pressure  Valve.  This  is  a  foim  of  lelief  valve  which 
is  placefl  in  the  outboard  e.xiiaust  pipe  to  prevent  the  jtressure  in 
the  heating  system  from  rising  above  a  given  point.  Its  office  is 
the  reverse  of  the  reducing  valve  which  supplies  more  steam  when 


HEATING  AND  VENTILATION. 


49 


the  pressure  becomes  too   low.      The  form   shown  in  Fig.  56  is 

designed  for  a  vertical  pipe.     Tlie  valve  proper  consists  of  two 

discs  of  unequal  area,  the  combined  area  of  which  equals  that  of 

the  pipe.     The  force  tending  to  open 

the  valve   is    that   due  to  the  steam 

pressure  acting  on  an  area  equal  to 

the  difference   in    area  between    the 

two    discs  ;  it  is  clear  from  the  cut 

that  the  pressure  acting  on  the  larger 

disc  tends    to  open  the  valve  while 

the    pressure  on  the  smaller  acts  in 

the  opposite    direction.      The   valve 

stem  is  connected  by  a  link  and  crank 

arm  with  a  spindle  upon  which  is  a  ^^' 

lever    and    weight    outside.       As    the    valve  opens    the    weight 

is  raised  so  that  by  placing  it  in  different  positions  on  the  lever 

arm   the    valve  will  open   at  any 
desired  pressure. 

Fig.  57  shows  a  different  type 
in  which  a  spring  is  used  instead 
of  a  weight.  This  valve  has  a 
single  disc  moving  in  a  vertical 
direction.  The  valve  stem  is  in 
the  form  of  a  piston  or  dash-pot 
which  prevents  a  too  sudden  move- 
ment and  makes  it  more  quiet  in 
its  action.  The  disc  is  held  on  its 
seat  against  the  steam  pressure  by 
a  lever  attached  to  the  spring  as 
shown.  When  the  pressure  of  the 
steam  on    tlie  underside    becomes 

greater  than  the  tension  of  the  spring,  the  valve  lifts  and  allows 

the  steam  to  escape.     The  tension  of  the  spring  can  be  varied  by 

means  of  the  adjusting  screw  at  its  upper  end. 

A  back  pressure  valve  is  simply  a  low  pressure  safety  valve 

designed  with  a  specially  large  opening  for  the  passage  of  steam 

through  it,     They  are  also  made  for  horizontal  pipes  as  well  as 

vertical. 


Fig.  57. 


50 


HEATING  AND  VENTILATION. 


Hxhaiist  Head.  This  is  a  I'onn  of  s('|):iriit()r  ])laco(l  at  the 
top  t>f  ail  outhoai'il  oxliaust  i>ii»o  to  jucvent  tlu'  water  carried  up 
in  the  steam  iVom  falling  upon  the  roofs  of  buildings  or  in  the 
street  below.  Fig.  58  is  known  as  a  centrifugal  exhaust  head. 
The  steam  on  entering  at  the  bottom  is  given  a  whirling  or  rotary 
motion  by  the  spiral  deflectors  and  the  water  is  thrown  outward 
by  centrifugal  force  against  the  sides  of  the  chamber  from  which 
it  tli»ws  into  the  shallow  trough  at  the  base  and  is  carried  away 
through  the  drip  pi{)e  wliicli  is  brought  down  and  connected  with 

a  drain  l)ii)e  inside  the  building.  The 
passage  of  the  steam  outboard  is  shown 
by  the  arrows.  Other  forms  are  used 
in  which  the  water  is  separated  from 
the  steam  by  deflectors  which  change 
the  direction  of  tin;  currents. 

Automatic  Return  Pumps.  In 
exhaust  heating  plants  the  condensation 
is  retuined  to  the  boilers  by  means  of 
some  foi-m  of  return  pump.  A  combined 
pump  and  I'cceiverof  the  form  illustrated 
in  Fig.  59  is  generally  used.  This  con- 
sists of  a  cast  or  wrought  iion  tank 
mounted  on  a  l)ase  in  connection  with 
a  boiler  feed  pump.  Inside  of  the 
tank  is  a  ball  float  connected  by  means  of  levers  with  a  valve 
in  the  steam  pipe  which  is  connected  with  the  puni]).  When 
the  water  line  in  tlie  tank  rises  above  a  certain  level,  the  float 
is  raised  and  opens  the  steam  valve  which  starts  the  pump. 
When  the  water  is  lowered  to  its  normal  level  the  valve  closes 
and  the  jjump  stops.  By  tliis  arrangement  a  constant  water  line 
is  maintjiined  in  the  receiver  and  the  pump  runs  only  as  needed 
to  care  for  the  condensation  as  it  i-eturns  from  the  heating  system. 
If  dry  returns  aie  used  they  ma}^  be  brought  together  and  con- 
nected with  the  top  of  the  receiver.  If  it  is  desired  to  seal  the 
horizontal  runs,  as  is  usually  the  case,  the  receiver  may  be  raised 
to  a  height  sufficient  to  give  the  required  elevation  and  the 
returns  connected  near  the  bottom  below  the  water  line. 

A  "  balance  pipe,"  so  called  should  connect  the  he^Vting  main 


Fifr.    58. 


HEATING  AND  VENTILATION. 


51 


with  the  top  of  the  tank  for  equahzing  the  pressure,  otherwise 
the  steam  above  the  water  would  condense  and  the  vacuum  thus 
formed  woukl  draw  all  the  vvater  into  the  tank  leaving  the  returns 
practically  empty  and  thus  destroying  the  condition  sought. 
Sometimes  an  independent  regulator  or  pump  governor  is  used  in 
place  of  a  receiver.      One  type  is  shown  in  Fig.  60.     The  return 


Fig.  59. 


main  is  connected  at  the  upper  opening  and  the  pump  suction 
with  the  lower.  A  float  inside  the  cliamber  operates  the  steam 
valve  shown  at  the  top  and  the  pump  works  automatically  as  in 
the  case  just  described. 

If  it  is  desired  to  raise  the  water  line  the  regulator  may  be 
elevated  to  the  desired  height  and  connections  made  as  shown  in 
Fig.  61. 

Return  Traps.  The  principle  of  the  return  trap  has  been 
described  in  "  Boiler  Accessories  "  but  its  practical  form  and  appli- 
cation will  be  taken  up  here.     The  type  shown  in  Fig.  62  has  all 


ni:.\'riX(;  axi>  \'i:\Tii.A'ri()\. 


of  its  workiiifj  parts  outside  of  the  trap.     It  consists  of  a  cast  iron 

Ixnvl  pivotod  at  G  and  II.  Tlieri'  is  :iii  opening  through  G  con- 
nect mil;'  w  itli  1  lie  inside  of  the  bowd. 
The  pil)e  K  connects  through  C 
with  an  intei'it)r  |)i|)e  oj)i'ning  near 
the  to[)  (^set'  Fig.  (;;'>.)  The  pipe 
1)  connects  with  a  receiver  into 
uhich  all  of  tlu-  returns  are 
brought.  A  is  a  check  valve 
allowing  water  to  pass  through  in 
the  direction  shown  hy  the  arrow. 
E  is  a  pipe  connecting  with  the 
boiler  below  the  water  line.  li 
Fig-  60.  is  a    clieck    opening    toward    the 

boiler  and  K  a  pipe  connected  with  the  steam  main  or  drum. 
The  action  of  the  trap  is  as  follows.     As  the  bowl  tills  with 

water  from  the  receiver  it  overl)alances  tlu;  weighted    lever  and 


A  U  TO  MA  T/C      VA  L  VE 

/ 


TO     PUMP 


FiK.   CI. 


drops  to  the  bottom  of  tiie  ring.  This  opens  the  valve  C  and 
admits  steam  at  boiler  pressure  to  the  top  of  the  trap.  Being  at 
a  higher  level  the  water  flows  by  gravity  into  the  boiler,  through 


tIEiATING  AND  VENTILATIOK^. 


53 


the  pipe  E.  Water  and  steam  are  kept  from  passing  out  through 
D  b}^  the  check  A. 

When  the  trap  has  emptied  itself  the  weight  of  tlie  ball  raises 
it  to  the  original  position,  which  movement  closes  the  valve  C  and 
opens  the  small  vent  F.  The  pressure 
in  the  bowl  being  relieved,  water  flows 
in  fi-om  the  receiver  through  D  until 
the  trap  is  filled,  when  the  j^rocess  is 
repeated.  In  order  to  work  satisfac- 
torily the  trap  should  be  placed  at  least 
3  feet  above  the  water  level  in  the 
boiler  and  the  pressure  in  the  returns 
must  always  be  sufficient  to  raise  the 
water  from  the  receiver  to  the  trap 
against  atmospheric  pressure  which  is 
theoretically  about  1  pound  for  every  2 

feet  in  height.  In  practice  there  will  be  more  or  less  friction  to 
overcome,  and  suitable  adjustments  must  be  made  for  each  particu- 
lar case.       Fig.   64   shows   another   form  acting  upon   the    same 


Fig.  62. 


Fig.  63. 


principle  except  in  this  case  the  steam  valve  is  operated  by  a 
bucket  or  float  inside  of  the  trap.  The  pipe  connections  are  prac- 
tically the  same  as  witli  the  trap  just  described. 


JIKATIN(;  AND  VENTILATION. 


Kt'tuni  traps  arc  nioii>  coiiuiiniily  used  in  siiiallci-  plants 
wluTi'  it  is  ili'sircd  to  avoid  tlu'  cxpfiist'  and  iar<'  of  a  [minp. 

Damper  Reyjulators.  I'.vt'rv  liratiiig  and  I'veiy  p()\ver  j)laiit 
sluMild  Ix'  pio\  itlcd  witli  aiitoniatic  means  for  ( losin<j;  tluMl.unpers 
wluMi  tlio  steam  pressure  reaches  a  certain  pnint.  and  for  opcnin*^ 
iheni  ag-.iin  when  the  pressure  drops.      There  are  various  rogulatoi's 


EXHAUST 


Fig.  64. 

designed  for   tliis  purpose,  a  simple    form   of  which  is  shown  in 
Fig.  65. 

Steam  at  boiler  pressuie  is  admitted  beneath  a  diaphragm 
which  is  balanced  Ijy  a  weighted  lever.  When  the  pressure  lises 
to  a  certain  point  it  raises  the  lever  slightly  and  opens  a  valve 
wliich  admits  water  under  pressure  above  a  diapliragm  located 
near  the  smokepipe.  This  action  forces  down  a  lever  connected 
by  chains  with  the  damper  and  closes  it.  When  the  steam  pressure 
drops,  the  water  valve  is  closed,  and  the  different  parts  of  the 


HEATING  AND  VENTILATION. 


55 


apparatus  take  their  original  positions.  Another  form  similar  in 
principle  is  shown  in  Fig.  66.  In  this  case  a  piston  is  operated 
by  the  water  pressure  instead  of  a  diaphragm.  In  both  types  the 
pressures  at  which  the  damper  shall  open  and  close  are  regulated 
by  suitable  adjustments  of  the  weights  upon  the  levers. 

Pipe  Connections.      The  method  of  making  the  pipe  connec- 
tions in  any  particular  case  Avill  depend  upon  the  general  arrange- 


^  ORIP 


Fig.  65. 


ment  of  the  apparatus  and  the  various  conditions.  Fig.  67  illus- 
trates the  general  principles  to  be  followed,  and  by  suitable 
changes  may  be  used  as  a  guide  in  the  design  of  new  systems. 

Steam  first  passes  from  the  boilers  into  a  large  drum  or 
header;  from  this  a  main,  provided  with  a  shut-off  valve,  is  taken 
as  shown ;  one  branch  is  carried  to  the  engines  while  another  is 
connected  with  the  heating  system  through  a  reducing  valve  hav- 
ing a  by-pass  and  cut-out  valves.  The  exhaust  from  the  engines 
connects  with  the  large  main  over  the  boilers  at  a  point  just  above 


56 


IIKATINC    AM)   VKNTILATIOK. 


HEATING  AND  VENTILATION. 


57 


the  steam  drum.  The  branch  at  the  right  is  carried  outboard 
through  a  back  pressure  valve  which  may  be  set  to  carry  any 
desired  pressure  on  the  system.  The  other  branch  at  the  left 
passes  through  an  oil  separator  into  the  heating  system.  The 
connections  between  the  mains  and  radiators  are  made  in  the 
usual  way  and  the  main  return  is  carried  back  to  the  return  pump 
near  the  floor.     A  false  water  line  or  seal  is  obtained  by  elevating 


Fio;.  66. 


the  pump  regulator  as  already  described.  An  equalizing  o^ 
balance  pipe  connects  the  top  of  the  regulator  with  the  low  pres- 
sure heating  main  and  high  pressure  is  supplied  to  the  pump  as 

shown. 

A  sight  feed  lubricator  sliould  be  placed  in  this  pipe  above 
the  automatic  valve,  and  a  valved  by-pass  should  be  placed  around 
the  regulator  for  running  the  pump  in  case  of  accident  or  repairs. 
The  oil  separator  should  be  drained  through  a  special  oil  trap  to  a 


IIKATING  AND  VENTILATION. 


ratoh  basin  or  to  tli«'  sewer,  ami  tin'  steam  (Iriiiii  or  any  other  low 
points  or  j>ork«'ts  in  the  hiiich  pressure  [lipint;-  dripped  to  the  main 
return  ihrouij;h  snitahle  tracts. 

.Moans  siiould  he  provided  tor  draining  all  [)arts  of  tlic  system 
lt>  ilie  sewer  and  all  trai)s  and  s[)eeial  apparatus  should  be  by- 
passed. The  return  pump  should  always  be  duplicated  in  a  plant 
«»f  any  size  as  a  safeguard  against  accident  and  the  two  pumps  run 
alternately  to  make  surt*  that  one  is  alwa3'S  in  working  order. 
One  piece  of  ap[)aratus  not  shown  in  Fig.  G7  is  the  feed  water 
heater.  If  all  of  the  exhaust  steam  can  be  utilized  for  heating 
purposes,  this  is  not  necessary  as  the  cold  water  for  feeding  the 
boilei-s  may  be  discharged  into  the  return  pipe  and  be  pumped  in 
with  the  condensation.  In  summer  time,  however,  when  the 
heating  plant  is  not  in  use,  a  feedwater  heater  is  necessary,  as  a 
large  amount  of  heat  which  Avould  otherwise  be  wasted  may  be 
saved  in  this  way.  The  connections  will  depend  somewhat  upon 
the  form  of  heater  used,  but  in  general  a  single  connection  with 
t!ie  heating  main  inside  the  back  pressure  valve  is  all  that  is  nec- 
essary. The  condensation  from  the  heater  should  be  trapped  to 
the  sewer. 


EXAMINATION  PAPER. 


HEATING  AND   VENTILATION   PART  II. 


HEATING  AND  VENTILATION, 


rkr.hrsamye"evloLly°en,you„,aybeused.     Attevcomplefogthe  wo.k 

nrirl  anrl  SI  en  the  followins  statement. 

'ihei'by  certify  that  tlie  above  work  is  entirely  my  own. 

(oigneci) 


1  How  would  you  obtain  the  sizes  of  the  cold  and  warm-, 
air  pipes  connecting  with  indirect  heaters  in  dwelling  house  work? 

2.     What  is  an  aspirating  coil  and  what  is  its  use  ? 

3  What  efficiencies  may  be  allowed  for  indirect  heaters 
iu  school  house  work?  How  would  you  compute  the  size  of  an 
indirect  heater  for  a  room  in  a  dwelling  house  ? 

4.     How  is  the  size  of  a  direct-indirect  radiator  computed? 

5  \  school  room  on  the  fourth  floor  is  to  be  supplied  with 
2400  cubic  feet  of  air  per  minute.     What  shotdd  be  the  area  of 

the  warm-air  supply  flue?  ,         ^  .    . 

Ans.   6  square  leet. 

6.  What  is  the  chief  objection  to  a  mixing  damper,  and 
how  may  this  be  overcome? 

7 '  How  many  square  feet  of  indirect  radiation  will  be  re- 
quired to  warm  and  ventilate  a  school  room  when  it  is  10  degrees 
below  zero,  if  the  heat  loss  through  walls  and  wmdows  is  42,000 

B    T.  U.,  and  the  air  snppb'  l'-^'^'^^^  «^^^^^«  ^^^^  P^'  ^'°'"' '         ,     . 

Ans.  349  square  feet. 

8  What  is  the  difference  in  construction  between  a  steam 
radiator  and  one  designed  for  hot  water  ?  Can  the  steam  radiator 
be  used  for  lu.t  water?     State  reasons  for  answer. 


62  HKATlNt;    WD   \  KNTILATION. 


9.      How  may  tlu>  piping  in  a  lint  watiT  systoiii  \)v  anau^cd 
so  tluit  no  air  valves  will  lu'  ii'iiuin'd  on  the  radiators? 

10.  What  eiru'ieney  is  eoininouly  ol)laiiu'd  iVom  adiivct  hot 
water  radiator?      How.  is  this  computed/ 

11.  Ilow  .shoidil  the  [)i()i's  he  t^raih'd  in  maUiiio;  the  connec- 
tions with  indireri  lu)t  water  ln-atcrs?  Where  should  the  air 
vahi-  he  I  "laced? 

111.      Descrihe  brielly  one  form  of  grease  extractor. 

l-'^>.  What  is  the  office  of  a  pressure  reducing  valve  in  an 
exhaust  steam  lieating  system  ? 

14.     Upon  what  principle  does  a  pump  governor  operate? 

lo.  What  type  of  pipe  fittings  should  always  be  used  in  hot 
water  work? 

It').  How  is  the  water  of  condensation  returned  to  the  boilers 
in  exliaust  steam  heating? 

IT.  How  many  cubic  feet  of  air  per  hour  will  be  discharged 
through  a  flue  2  feet  by  3  feet  and  60  feet  high,  if  the  air  in  the 
flue  lias  a  temperature  of  80  degrees  and  the  outside  air  GO 
degrees  ? 

Ans.  13-1,280  cubic  feet. 

18.  In  a  hot  water  heating  system  what  causes  the  water  to 
flow  through  the  pipes  and  radiators?  How  does  the  height  of 
the  radiator  above  the  boiler  effect  the  flow  ? 

19.  What  precaution  should  always  be  taken  before  starting 
a  fire  under  a  steam  boiler? 

20.  What  is  the  free  opening  in  square  feet  through  a 
register  24  inches  by  48  inches?  Ans.  5.3  square  feet. 

21.  Why  are  return  j)umps  or  return  traps  necessary  in 
exliaust  steam  heating  plants  ? 

22.  What  efficiency  may  be  obtained  from  indirect  hot 
water  radiators  under  usual  conditions  ?  What  is  the  common 
method  of  computing  indirect  hot  water  surface  for  dwelling  house 
work  ? 

23.  SL'^ite  biielly  how  a  retuin  trap  operates. 

24.  What  is  the  use  of  an  expansion  tank,  and  what  slujuld 
be  its  capacity  ? 

25.  Descril>e  the  action  of  one  form  of  damper  regulator. 


HEATING  AND  VENTILATION.  63 


26.  What  is  the  principal  difference  between  a  hot  water 
heater  and  a  steam  boiler  ?  What  type  of  heater  is  best  adapted 
to  the  warming  of  dwelling  houses  ? 

27.  Upon  what  four  conditions  does  the  size  of  a  pipe  to 
supply  any  given  radiator  depend? 

28.  What  is  the  use  of  an  exhaust  head? 

29.  A  hospital  ward  requires  60,000  cubic  feet  of  air  per 
hour  for  ventilation,  and  the  heat  loss  through  walls  and  windows 
is  140,000  B.  T.  U.  per  hour.  How  many  square  feet  of  indirect 
radiation  will  be  required  in  zero  weather  ? 

Ans.  491  sq.  ft. 

30.  For  what  purpose  is  a  back-pressure  valve  used? 

31.  A  hospital  ward  is  warmed  by  direct  heat  and  it  is 
desired  to  add  ventilation  by  using  indirect  radiators  for  warming 
the  air  supply.  The  ward  has  20  occupants.  How  many  square 
feet  of  indirect  surface  will  be  required  when  it  is  10  degrees 
below  zero,  allowing  an  efficiency  of  660  ? 

Ans.  220  sq.  ft. 

32.  A  first  floor  class-room  in  a  high  school  had  40  pupils, 
how  many  square  feet  area  should  the  vent  flue  have  ? 

Ans.  5.8  sq.  ft. 

33.  A  private  grammar  school  room  having  15  pupils  is 
heated  by  direct  hot  water.  It  is  decided  to  increase  the  size  of 
boiler  and  introduce  ventilation  by  means  of  indirect  hot  water 
radiation.  How  many  more  square  feet  of  grate  surface  will  be 
required  in  the  new  boiler  for  zero  weather  ? 

Ans.  1.4  sq.  ft. 


HEATING  AND   VENTILATION 


PART     III 


INSTRUCTION     PAPER 


AMERICAN      SCHOOL     OF      CORRESPONDENCE 

[chartered  bv  the  commonwelalth  ok  Massachusetts] 

BOSTON,     MASSACHUSETTS 
U  .    S  .    A  . 


Prepared  By 

Chaki.es  ly.  Hubbard,   M.E., 

OF 

S.  Homer  VVoodbridge  Company, 
Heating,  Vp;ntilation  and  Sanitary  Engineers. 


HEATING  AND  VENTILATION. 


VACUUM  SYSTEMS. 


Lx)w  Pressure  or  Vacuum  Systems.     In  the  systems  of  steam 
heating  which  have  been  described  up  to  this  point  the  pressure 
carried  has  always  been  above  that  of  the  atmosphere,   and   the 
action  of  gravity  has  been  depended  upon  to  carry  the  water  of 
condensation  back  to  the  boiler  or  receiver ;  the  air  in  the  radiators 
has  been  forced  out  through  air  valves  by  the  pressure  of  steam 
back  of  it.     Methods  will  now  be  taken  up  in  which  the  pressure 
in  the  heating  system  is  less  than  the 
atmosphere  and  where  the  circulation 
through  the  radiators  is  produced  by 
suction     rather    than     by    pressure. 
Systems    of    this  kind    have    several 
advantages  over  the  ordinary  methods 
of  circulation  under  pressure.      First 
—  no    back    pressure  is  produced  at 
the  engines  when  used  in  connection 
with  exhaust  steam,  but  rather  there 
will  be  a  reduction  of  pressure  due  to 
the    partial    vacuum  existing  in   the 
radiators;    second  —  a    complete   re- 
moval of  air  from  the  coils  and  radiators  so  that  all  portions  are 
steam  filled  and  available  for  heating  purposes  ;  third  —  complete 
drainage  through  the  returns,  especially  those  having  long  hori- 
zontal runs,  and  the  absence  of  water  hammer ;  and  fourth  the 
smaller  size  of  return  pipes  necessary.      The  two  systems  of  this 
kind  in  most  common  use  are  known  as  the  Webster  and  Paul 
systems. 

Webster  System.  This  consists  primarily  of  an  autouiatic 
outlet  valve  on  each  coil  and  radiator  connected  with  some  form  of 
suction  aj)paratus  such  as  a  pump  or  ejector.  The  vnlve  used  is 
shown  in  section  in  Fig.  1   and  replaces  the  usual  baud  valve  at 


Fiff.  1. 


lIKA'riNc;    AM)    \  KXTILAriOX. 


HEATING  AND  VENTILATION, 


the  return  end  of  the  radiator.  It  is  .similar  in  construction  to 
some  of  the  air  valves  already  descril)ed,  consisting  of  a  rub])er  or 
vulcanite  stem  closing  against  ;i  valve  opening  when  made  to  ex- 
pand hy  the  presence  of  steam.  When  water  or  ah-  fills  the  valve 
the  stem  contracts  and  allows  them  to  be  sucked  out  as  shown  by 
the  arrows.  A  perforated  metal  strainer  surrounds  the  stem  or 
expansion  piece  to  prevent  dirt  and  sediment  from  clogging  the 
valve. 


Fiff.  2. 


Fig.  .3. 


Fig.  2  shows  tlie  valve,  or  thermostat  as  it  is  called,  attached 
to  an  ordinary  angle  valve  with  the  top  removed,  and  Fig.  3  in- 
dicates the  method  of  draining  the  bottoms  of  risers  or  the  ends  of 
mains. 

One  special  advantage  claimed  for  this  system  is  that  the 
amount  of  steam  admitted  to  the  radiators  may  be  regulated  to 
suit  the  requirements  of  outside  temperature,  and  this  may  be  done 
without  water  logging  or  hammering,  a  result  impossible  to  obtain 
with  any  other  combination  of  steam  heating  apparatus.  This 
may  be  done  at  will  by  closing  down  on  the  inlet  supply  to  the 
desired  degree.  The  result  is  the  admission  of  a  smaller  amount 
of  steam  to  the  radiator  than  it  is  calculated  to  condense  normally. 
The  condensation  is  removed  as  fast  as  formed  by  the  opening  of 
the  thermostatic  valve. 


IIKATINU  AND  VENTILATION, 


The  uftMicnil  ;ip]>lii'alioii  of  (lii.s  systt'iii  ((»  cxliaiist  hcaiiiiL;-  is 
shown  ill  Ki^'.  1.  I'xhaiist  stfam  is  hroiiLjlit.  iVoni  the  ciiqiiit'  as 
sliowii  :  Olio  l)nuu  li  is  i-oniu'clod  with  a  fccd-watn-  licator  while 
the  other  is  i-arried  iij^wanl  and  throu^'h  a  L,'rease  exli-aclor  where 
it  hranehes  a^^ain,  one  line  leading  onll)onn(l  thrnui^di  a  hack- 
pressure  valve  and  the  other  eonnecting  with  thi;  heating  main. 
A  live  steam  connection  is  made  throuo'h  a  reducincf  valve  as  in 
the  ordinary  system.  Valved  connections  are  made  witli  the 
eoils  ami  radiators  in  tlie  usual  maimer  hut  the  icturii  valves  are 
replaced  by  the  special  thermostatic  valves  described  al)ove. 

The  main  return  is  brought  down  to  a  vacuum  pump  which 
discharges  into  a  "•  returns  tank"  where  the  air  is  separated  from 
tlie  water  and  passes  off  through  the  vapor  pipe  at  the  top.  The 
condensation  then  flows  into  the  feed  water  heater  from  which  it 
is  automatically  pumped  back  into  tlie  boilers.  The  cold-water 
feed  supply  is  connected  with  the  returns  tank  and  a  small  cold- 
■water  jet  is  connected  into  the  suction  at  the  vacuum  pump  for 
increasing  the  vacuum  iu  the  heating  system  by  the  condensation 
of  steam  at  this  point. 

Paul  System.  In  this  system  the  suction  is  connected  with 
the  air  valves  instead  of  the  returns  and  the  vacuum  is  produced 
by  means  of  a  steam  ejector  instead  of  a  puinj).  The  returns  are 
carried  back  to  a  receiving  tank  and  pumped  back  to  the  boiler  in 
the  usual  manner.    The  ejector  in  this  case  is  called  the  'Mixhauster.'' 

Fig.  5  shows  the  general  method  of  making  the  pipe  con- 
nections with  radiatore  in  this  system  and  Fig.  G  the  details  of 
connection  at  the  exhauster. 

A  A  are  the  returns  from  the  air  valves  and  connect  with 
the  exhausters  as  shown.  Live  steam  is  admitted  in  small  quan- 
tities through  the  valves  B  B  and  the  mixture  of  air  and  steam  is 
discharged  outboard  through  the  j)ipe  (J.  1)  I)  are  gag(!S  showing 
the  pressure  in  the  system  and  E  E  are  check  valves.  The  advan- 
tage of  this  system  depeods  principally  upon  the  quick  removal  of 
air  from  the  various  radiators  and  pipes  which  constitutes  tlie 
principal  obstruction  to  circulation  ;  the  inductive  action  in  many 
ca.ses  is  sufficient  to  cause  the  system  to  oj)erate  somewhat  below 
atmospheric  pressure. 


HEATING  AND  VENTILATION. 


Where  exhaust  steam  is  used  for  heating,  the  radiators  should 
be  somewhat  increased  in  size  owing  to  the  lower  temperature  of 


PAUL     SYSTEM   OF  HEATINO 


Fijr.  5. 


the  steam.     It  is  common  practice  to  add  from  20  to  30  per  cent. 
to  the  sizes  required  for  low  pressure  live  steam. 


UK  ATI  \(  J  AND  VENTII.  ATIONT. 


FORCHD    BLA5T. 

In  ;i  sNstoni  of  roict'd  firculalioii  liv  means  (•!"  a  fan  or  Itlowor 
tlie  action  is  positive  aiitl  inaclieally  eoiistaiil  umler  all  usual  con- 
ditions of  outside  temperature  and  wind  action.  This  gives  it  a 
decided  advantage  over  natuial  or  gravity  mctliods  which  are 
affected  to  a  greater  or  less  degree  l)y  changes  in  wind  pressure^ 


and  makes  it  especially  adapted  to  the  ventilation  and  warming  of 
large  buildings  such  as  shops,  factories,  schools,  churches,  halls, 
theatres,  etc.,  where  large  and  delinitf;  air  fpiantities  are  required. 


HEATING  AND  VENTILATION. 


9 


Exhaust  Method.  This  consists  in  drawing  the  air  out  of  a 
building  and  providing  for  the  heat  thus  carried  away  by  placing 
steam  coils  under  Avindows  or  in  other  positions  where  the  inward 
leakage  is  supposed  to  be  the  greatest.  When  this  method  is 
used  a  partial  vacuum  is  created  within  the  building  or  room  and 


Fig.  7. 


all  currents  and  leaks  are  inward ;  there  is  nothing  to  govern 
definitely  the  quality  and  place  of  introduction  of  the  air,  and  it 
is  difficult  to  provide  suitable  means  for  warming  it. 

Plenum  Method.  In  this  case  the  air  is  forced  into  the 
building,  and  its  quality,  temperature  and  point  of  admission  are 
completely  under  control.  All  spaces  are  filled  with  air  under  a 
slight  pressure  and  the  leakage  is  outward,  thus  preventing  the 
drawing  of  foul  air  into  the  room  from  any  outside  source.  But 
above  all,  ample  opportunity  is  given  for  properly  warming  the 


hi 


llliAriNCi  AND  VENTILATION. 


air  l>v  nu'Miis  of   luMlcrs,  rillicr   in   diiccl    ciuiiicctinii    with  tin-  fan 
or  in  scparati*  passajj^t's  It'adiiiLj  to  tlio  various  rooms. 

Fonn  of  Heating  5urface.        A   common    foiiii   of   heater  for 


^'SS^ 


<^.     ■>. 


forced  blast  heating  i.s  shown  in  Fig.  16,  Part  I.  This  consists  of 
sectional  cast-iron  bases  witli  loops  of  wrought-iron  pii)e  connected 
as  shown.     The  steam    enters    the    upper    part  of    the    bases  or 


HEATING  AND  VENTILATION. 


11 


headers  and  passes  up  one  side  of  the  loops,  then  across  the  top 
and  down  on  the  other  side  where  the  condensation  is  taken  off 
through  the  return  drip,  which  is  separated  from  the  inlet  by  a 
partition.  These  heaters  are  made  up  in  sections  of  2  and  4  rows 
of  pipes  each.  Tlie  lieight  varies  from  3.1-  to  9  feet  and  the  width 
from  3  feet  to  7  feet  in  tlie  standard  sizes.  They  are  usually- 
made  up  of  1-inch  pipe  although  1^  inch  is  commonly  used  in  the 
larsrer  sizes.  In  Figp.  7  is  shown  a  similar  heater.  This  is  ar- 
ranged  for  supplying  exhaust  to  a  portion  of  the  sections  and  live 
steam  to  the  remainder.  The  division  between  the  two  sections 
is  shown  wliere  the  metal  is  broken  away.      Fig.    8   shows  still 


FRONT  v/e:w 


A/R  valve:  i 

PLAN  AT  SUPPLY  ENO 


TO  SEWEP:i 


S/OE      V/EW 


Fig.  9. 
another  form;  in  this  case  all  of  the  loops  are  made  of  practically 
the  same  length  by  the  special  form  of  construction  shown.     This 
is  claimed  to  prevent  the  short  circuiting  of  steam  through  the 
shorter  loops  which  causes  the  outer  pipes  to  remain  cold. 

This  form  of  heater  is  usually  encased  in  a  sheet  steel  hous- 
ing as  shown,  but  may  be  supported  on  a  foundation  between 
brick  walls  if  desired. 

Fig.  0  sliows  a  special  form  of  heater  particularly  adapted  to" 
ventilatintj  work  where  tlie  air  does  not  have  to  be  raised  above 


12  llKA'ri\(;    AND   \K\'riI.ATI()\. 

70  or  80  deprives.  Ii  is  iiiado  up  «>!'  l-iiidi  w  rounlit-iroii  i)ipe 
i-ouiu'cUmI  with  su|i{tly  and  roliini  licadtMs:  cadi  st'rtioii  coiitaiiis 
14  pijjt's  ami  tlicy  arc  iisuall\  iiiatlc  up  in  -groups  of  .)  st'dions 
oai'li.  Tlu'so  (.•(ills  ari*  sup[)()rlo(l  upon  tci;  irons  i-c^sting  u})()U  a 
brirk  fouiulatioM.  Heaters  of  tliis  form  arc^  nsnally  made  to 
extend  aeniss  the  side  of  a  mom  wiih  Itrick  walls  al  the  sides 
instead  of  heinj^  enciised  in  steel  housint^s.  Heaters  made  up  of 
bunks  of  the  sehool-j)in  east-iron  radiators  give  excellent  results 
for  sehoolhouse  work.  The  sections  shouhl  be  so  arran<red  that 
the  free  area  for  air  tlow  shall  not  be  too  mnch  ivstricted. 

Efficiency  of  Heaters.  The  eilficieney  of  the  heater.s  used  in 
connection  with  forced  blast  varies  greatly,  depending  upon  the 
temperature  of  tlie  entering  air,  its  velocity  between  tlu;  pipes, 
tlie  temperature  to  which  it  is  raised  and  the  steam  pressure  car- 
ried in  the  heater.  The  general  method  in  which  the  lieater  is 
made  up  is  also  an  important  factor. 

In  designing  a  heater  of  this  kind,  care  must  be  tak(Mi  that 
the  free  area  between  the  pipes  is  not  contracted  to  such  an 
extent  that  an  excessive  velocity  will  be  required  to  pass  the  given 
quantity  of  air  through  it.  In  ordinary  work  it  is  customary  to 
assume  a  velocity  of  800  to  1000  feet  per  minute  ;  higher  velocities 
call  for  a  greater  pressure  on  the  fan  which  is  not  desirable  in 
ventilating  work. 

In  the  lieaters  shown,  about  .4  of  the  total  area  is  free  for  the 
passage  of  air  ;  that  is,  a  heater  5  feet  wide  and  6  feet  high  would 
have  a  total  area  of  5  X  6  i=  30  square  feet,  and  a  free  area 
between  the  pipes  of  30  X  .4  —  12  square  feet.  The  depth  or 
numtxjr  of  rows  of  pipe  does  not  effect  the  free  area  although  the 
friction  is  increased  and  additional  work  is  thrown  upon  the  fan. 
The  efficiency  in  any  given  heater  will  be  increased  by  increasing 
the  velocity  of  the  air  thi-ough  it,  l)ut  tlie  final  temperature  will 
Ije  diminislied,  that  is,  a  larger  quantity  of  air  will  be  heated  to  a 
lower  temperature  in  the  second  case  and  while  the  total  heat 
given  off  is  greater,  the  air  quantity  increases  more  rapidl}-^  than 
the  heat  quantity  which  causes  a  drop  in  temperature. 

Increasing  the  number  of  rows  of  pipe  in  a  heater  with  a 
constant  air  quantity  increases  the  final  temperature  of  the  air  but 
diminishes  the  efficiency  ai  the  heater,  because  the  average  differ- 


HEATING  AND  VENTILATION. 


13 


ence  in  temperature  between  the  air  and  steam  is  less.  Increas- 
ing the  steam  pressure  in  the  heater  (and  consequently  its  temper- 
ature) increases  both  the  final  temperature  of  the  air  and  the  effi- 
ciency of  the  heater.  Table  I  has  been  prepared  from  different 
tests  and  may  be  used  as  a  guide  in  computing  probable  results 
under  ordinary  working  conditions.  In  this  table  it  is  assumed 
that  the  air  enters  the  heater  at  a  temperature  of  10  degrees 
below  zero  and  passes  between  the  pipes  with  a  velocity  of  800 
feet  per  minute.  Column  1  gives  the  number  of  rows  of  pipe  in 
the  heater  and  columns  2,  3  and  4  the  final  temperature  of  the  air 
for  different  steam  pressures.  Columns  5,  6  and  7  give  the 
corresponding  efficiency  of  the  heater. 

For  example.  Air  passing  through  a  heater  10  pipes  deep 
and  carrying  20  pounds  pressure  will  be  raised  to  a  temperature 
of  90  degrees  and  the  heater  will  have  an  efficiency  of  1650  B.T.U. 
per  square  foot  of  surface  per  hour.  When  the  air  is  taken  in  at 
zero  we  may  add  10  to  the  final  temperatures  given  in  the  table, 
although  theoretically  it  would  be  slightly  less  ;  in  this  case  we 
must  take  the  efficiency  corresponding  to  the  final  temperature 
after  the  10  degress  have  been  added. 

TABLE  I. 

Temp,  of  entering  air  10°  below  zero. 

Velocity  of  air  between  the  pipes  800  feet  per  minute. 


Temp,  to  which  the  air  win  be 
raised  from  W  below  0. 

Efficiency  of  the  heating  surface  in  B.  T.  U., 
per  square  foot  per  hour. 

Rows    of 
pipe  deep. 

Steam  Pressure  in  Heater. 

steam  Pressure  in  Heater. 

5  lbs. 

20  lbs. 

60  lbs. 

5  lbs. 

20  lbs. 

60  lbs. 

4 

30 

35 

45 

1600 

1800 

2000 

6 

50 

55 

65 

1600 

1800 

2000 

8 

6r> 

70 

85 

1500 

1650 

1850 

10 

80 

90 

.  105 

1500 

1650 

1850 

12 

95 

105 

125 

1500 

1650 

1850 

14 

105 

120 

140 

1400 

1500 

1700 

16 

120 

130 

150 

1400 

1500 

1700 

18 

130 

140 

160 

1300 

1400 

1600 

20 

140 

150 

170 

1300 

1400 

1600 

14  HKAriNci    AM)  VENTI  i.  ATK  )\'. 


l-'«>r  a  M'lority  <>t"  10<M>  I'crl.  iiiult  iply  tlu'  fciii/irrdl iircx  ^-ivcH 
ill  tlu'  tal)li'  Ity  .IT)  and  tlu'  ,tjlcii'ti<-ifs  hy  1.1:'>. 

ICxaniplc.  H(t\v  many  s(|iiart'  feet  of  radiation  will  Ix;  i-e- 
quiix'tl  to  raisi'  (!(»(), 000  cuhic  I'l'L't  ol"  air  per  hour  from  10  1k;1ow 
zero  t(»  SO  di>oriv«>s,  with  a  velocity  through  (he  heater  of  800  feet 
per  minute  and  a  steam  ]»res.sure  of  .")  jtounds  ?  What  nuist  In' 
tlie  total  area  of  the  heater  front  and  Imw  man}-  rows  of  ]»i{)es 
nuist  it  liave  ? 

Referring  hack  to  our  formula  for  heat  recpiired  for  ventila- 
tion, we  have 

000,000  X  00        oei  aieu  -r    tt  •     i 
:=  J>M1,»18  li.  i.  U.  I'equired. 

Referring  to  table  I  we  iiud  that  for  the  above  conditions  a 
heater  10  pipes  deep  is  required,  and  that  an  efficiency  of  1500 

B.  T.  r.  will  l)e  obti'.ined.      Then  '- !^ =  654  square  feet  of 

1500  ^ 

f  .  ,         600,000  iAAAA  1-  P        •  •  .  A 

suriace  requn-ed,    ~ =  10,000  cubic  of  air  per  minute,  and 

10,000        .  ^  -  f    ^     t    f  •      1    ^1  1,    .1 

. =  l-.o   square   leet  ot    tree    area   required   through   tlie 

800  ^  ^ 

heater.      If  we  assume  .4  of  the  total  heater  front  to  be  free  for 

the  passage  of  air,  then     "'     =  31  the  recpiiied  total  area. 

.4 

For  convenience  in  estimating  the  approximate  dimensions 
of  a  heater,  the  following  table  is  given.  The  standard  heaters 
made  by  different  manufacturers  vary  somewhat,  but  the  dimen- 
sions given  below  represent  average  practice.  Column  3  gives 
the  square  feet  of  heating  surface  in  a  single  low  of  [)ipes  of  the 
dimensions  given  in  columns  1  and  2,  and  column  4  gives  the  free 
area  between  the  pipes. 


HEATING  AND  VENTILATION. 


TABLE  II. 


15 


Width  of  Section. 

Height  of  Pipes. 

Square  Feet  of 
Surface. 

Free  Area  through 
Heater  in  Sq.  Ft. 

3  feet 

3  ft.  6  inches 

20 

4.2 

3  feet 

4  ft.  0  iiiclies 

22 

4.8 

3  feet 

4  ft.  6  inches 

25 

5.4 

3  feet 

5  ft.  0  inches 

28 

6.0 

4  feet 

4  ft.  6  inches 

34 

7.2 

4  feet 

5  ft.  0  inches 

38 

8.0 

4  feet 

5  ft.  6  inches 

42 

8.8 

4  feet 

6  ft.  0  inches 

45 

9.6 

5  feet 

5  ft.  6  inches 

52 

11.0 

5  feet 

6  ft.  0  inches 

57 

12-.0 

5  feet 

6  ft.  6  inches 

62 

13.0 

5  feet 

7  ft.  0  inches 

67 

14.0 

6  feet 

6  ft.  6  inches 

75 

15.6 

6  feet 

7  ft.  0  inches 

81 

16.8 

6  feet 

7  ft.  6  inches 

87 

18.0 

6  feet 

8  ft.  0  inches 

92 

19.2 

7  feet 

7  ft.  6  inches 

"98 

21.0 

7  feet 

8  ft.  0  inches 

108 

22.4 

7  feet 

8  ft.  6  inches 

109 

23.8 

7  feet 

9  ft.  0  inches 

116 

25.2 

In  calculating  the  total  height  of  the  heater  add  1  foot  for 
the  base. 

These  sections  are  made  up  of  1-inch  pipe  except  the  last,  or 
7-foot  sections,  which  are  made  of  1 1 -inch  pipe. 

Using  this  table  in  connection  with  the  example  just  given 
we  should  look  in  the  last  column  for  a  section  having  a  free  area 
of  12.5  squai-e  feet ;  here  we  find  that  a  5  feet  X  6  feet  —  6  inches 
section  has  a  free  opening  of  13  square  feet  and  a  radiating  surface 
of  62  square  feet.  The  conditions  call  for  10  rows  of  pipes  and 
10  X  62  rr:  620  square  feet  of  radiating  surface  which  is  slightly 
less  than  called  for,  but  which  would  be  near  enough  for  all  prac- 
tical purposes. 


16 


IIEATIN*.   AM)   \  KN  ril.A'n(>N. 


EXAMPLR  FOR  PRACTICE. 

1.  Coinimtt'  till'  (limt'iisioiis  of  a  licalrr  to  warm  20,000 
cubic  foct  el  air  iicr  niiiiutt'  from  li>  lu'low  /amo  to  TO  degrees 
wiili  '20  pounds  steam  [>ressure. 

Aus.      lO.")!  s(i.  feet  of  rad.  siirfaec  S  pipes  deep. 
'2')  «([.  ft.  frec^  area  tliroii^ii  heater. 
Use    sixteen   .">'  X  7'  sections,  side  by  side,   which  gives  28 
square  feet  area  anil  1<»T-  square  feet  of  surface. 


r 

r 

J L^_    5 i 

f 5    - 

, 

r» 

t^ 

i 

i 

- 

a  /'/pss  oc£p 


fRONT  rtev. 


S/D£  £L£V 


The  general  method  of  comi)uting  the  size  of  lieater  for  any 
given  buihling  is  the  same  as  in  the  case  of  indirect  heating: 
First  obtain  the  B.T.U.  required  for  ventilation  and  to  that  add 
the  heat  loss  througli  walls,  etc.,  and  divide  the  result  by  the 
efficiency  of  the  lieater  under  the  given  conditions. 

Example. —  An  audience  hall  is  to  be  provided  with  400,000 
cubic  feet  of  air  i)er  hour.  The  heat  loss  through  walls,  etc.,  is 
2'j0,000  B.T.U.  per  hour  in  zero  weather.  What  will  be  the  size 
of  heater,  and  how  many  rows  of  pipe  deep  must  it  be,  with  20 
pounds  steam  pressure. 
400,000  X  TO 


=  .^09,090  H.T.U..  for  ventilation. 


.').-) 


Tiierefore  250,000  +  509,000  =  T59,090  P,.T.ri.,  tf)tal  to  be 
supplied. 

We  must  next  find  to  what  temperature  the  entering  air 
must  1)6  raised  in  order  to  bring  in  the  required  amount  of  heat, 
>o  that  the  number  of  rows  of  pipe  in  the  heater  may  be  obtained 
and  its  corresponding  efficiet)cy  determined.  We  have  entering 
tlie  room  for  purposes  of  ventilation,  400. OOO  cubic  feet  of  air 
every  liour  at  a  temperature  of  TO  degrees,  and  the  probleni  now 


HEATING  AND  VENTILATION. 


r 


becomes,  to  what  temperature  must  this  air  be  raised  to  carry  in 
250,000  B.T.U.  additional  for  warming? 

'  We  have  learned  that  1  B.T.U.  will  raise  55  cubic  feet  of  air 
1  degree.  Then  250,000  B.T.U.  would  raise  250,000  X  55  cubic 
feet  of  air  1  degree. 

250,000  X  55  ^  g_^    , 
400,000 

The  air  in  this  case  must  be  raised  to  70  +  34  =  104  degrees 
to  provide  for  both  ventilation  and  warming.  Referring  to  table  I 
we  find  that  a  heater  12  pipes  deep  will  be  required  and  that  the 
corresponding  efficiency  of  the  heater  will  be  1650  B.T.U. 

Then  ^^^^^^  =  460  square  feet  of  surface  required. 
1650 

Pipe  Connections.  In  the  heater  shown  in  Fig.  16,  Part  I, 
all  of  the  sections  take  their  supply  from  a  common  header  ;  the 
supply  pipe  connecting  with  the  top,  and  the  return  being  taken 
from  the  lower  division  at  the  end,  as  shown. 

In  Fig.  7  the  base  is  divided  into  two  parts,  one  for  live 
steam  and  the  other  for  exhaust.  The  supply  pipes  connect  with 
the  upper  compartments  and  the  drips  are  taken  off  as  shown. 
Separate  traps  should  be  provided  for  the  two  pressures. 

The  connections  in  Fig.  8  are  similar  to  those  just  described 
except  the  supply  and  return  headers,  or  bases,  are  drained  through 
separate  pipes  and  traps ;  there  being  a  slight  difference  in  pres- 
sure between  the  two  which  is  likely  to  interfere  with  the  proper 
drainage  if  brought  into  the  same  one.  This  heater  is  arranged 
to  take  exhaust  steam  but  has  a  connection  for  feeding  in  live 
steam  through  a  reducing  valve  if  desired  ;  the  whole  heater  being 
under  one  pressure. 

It  is  often  desirable  to  have  a  heater  connected  up  in  sections 
so  that  one  or  more  can  be  shut  off  in  mild  weather  when  the 
whole  capacity  of  the  heater  is  not  required.  In  this  case  each 
section  has  separate  connections  with  valves  in  supply  and  return. 
Fig.  10  shows  an  excellent  metliod  of  making  the  connections  for 
a  heater  using  both  live  and  exhaust  steam  as  in  this  way  any 
number  of  sections  may  be  used  for  exhaust  from  one  to  the  entire 
heater  by  a  proper  adjustment  of  the  valves. 


18 


IlllATINC    A\l)    \  I'ATII.A'riON. 


The  usual  t'oniu'i'iioiis  in  l-'i<^'.  i>  ai-c  j»lainlv  shown.  A  su[i|)ly 
hoailtM-  runs  ;utoss  thi>  front  of  the  licatri-  fioni  which  \;ilvi'(l 
hnuuht's  arc  taken  olT  to  tlic  several  l;'1'oii|)s.  The  i-etnni  pipes 
have  cfoss  i'onnei'tu)ns  willi  the  sewci-  nr  (bain  for  hlowinLi;  out 
the  air  when  steam  is  th-sl  turned  on.  Two  or  nion;  yroups 
shouhl  l)e  connected  for  the  use  of  i'iiher  exhaust  or  live  steam  as 
shown  in  Fig.  1<>,  and  separate  traps  slioulil  he  jnoviih'd  for  the 
two   j)ressnres.      I^arj^e   and    freely    workin^f  automatic   air   valves 


live:  bt£-am 


eXHAUST  STEAM 


Fi-.  10. 


shouhl  he  provided  in  the  return  header  of  eacli  section  or 
group,  Avhatever  tlie  type  of  heater,  and  it  is  well  also  to  piovide 
liand  j>et  cocks  for  f»pening  when  steam  is  first  turned  on.  The 
form  of  lieater  shown  in  Fig.  0  is  espcjcially  efTieient  and  may  he 
relied  upon  to  give  an  efTiciency  of  about  1800  B.T.U.  and  to 
raise  the  air  from  zero  to  80°  with  a  velocity  of  800  feet  between 
the  pi[)es  and  a  steam  pressure  of  20  pounds.  A  cast-iron  sectional 
heater  will  give  about  loOO  H.T.U  under  the  same  conditions. 

Pipe  Sizes.  Tiie  pipe  sizes  required  in  this  system  of  heat- 
ing may  Ixi  computed  fjom  the  tallies  already  given.  The  leiigth 
of  run  from  the  lx)iler  or  main,  the  pressure  carried  and  the  allow- 
able drop  are  the  factoi-s  governing  tlie  size  of  the  main  suj)ply 
and   branches.      Heaters  of  the  pattern  shown  in   Figs.  7  and  10 


HEATING  AND  VENTILATION. 


19 


are  usually  tajjped  at  the 
factory  for  high  or  low 
pressure  as  desired  and 
these  sizes  may  be  followed 
in  making  the  pipe  con- 
nections. 

The  sizes  marked  on 
Fig.  9  may  be  used  for  all 
ordinary  work  where  the 
pressure  runs  from  5  to  20 
pounds  ;  for  pressures 
above  that  the  supply  con- 
nections may  be  reduced 
one  size. 

Fans  and  Blowers. 
The  term  fan  is  commonly 
applied  to  any  form  of  ap- 
paratus for  moving  air  in 
which  revolving  blades  or 


COLD   A/f>  IfJLCr  V^/NDOWS 


'  DISCHAPEC 
DUCr  ffOft 
BlOVVSf)  ArC£/Uli/G 

Tiir.  12. 


Fig.   11. 

propellers  are  used, 
while  the  word  blower  is 
used  only  in  those  cases 
where  the  Avheel  or  pro- 
peller is  enclosed  in  a 
casing. 

Referring  to  Part  I, 
Fig.  17  shows  the  usual 
form  of  fan  or  wheel 
used  in  the  common 
type  of  bloAver  and 
Fig.  11  represents  the 
usual  form  of  a  regular 
steel  plate  blower  with 
full  housing.  Where  a 
blower  is  connected  with 
a  heater  having  a  steel 
plate  casing  it  has  an 
inlet  onl}^  on  one  side, 


•J(t 


Ill'.ATINC    AM)    \  KXriLAI'lOX, 


but  when   um-iI  hi   (■< t-i-tion  with  a  hotitor  of  tlio  fy]^o  shown  in 

Fiij.  0  it  should  havo   inU't  openings  upon  l)(>lh  sides  as  shown  in 

Ficr.    12. 


The  discharge  ojjening  can  be  made  in  any  position  desired, 
either  up,  drnvn,  top  hoiizontal,  Ijottoni  liorizonlal  or  at  any  angle. 
Pig.  13  shows  a  top  horizontal  discharge  blower  connected  with  a 
heater. 


HEATING  AND  VENTILATION. 


21 


Where  the  height  of  the  fan  room  is  limited,  a  form  called 
the  three-quarter  housing  may  be  used  in  which  the  lower  part  of 
the  casing  is  replaced  bj-  a  brick  pit  belo\y  the  floor  level.  Such 
a  construction  is  shown  in  Fig.  14  with  a  direct-connected  engine. 
Another  type  of  fan  known  as  a  disc  wheel  may  be  used  where 
the  air  passages  are  large  and  the  resistance  to  air  flow  is  small, 
but  for  ordinary  ventilating  work  the  encased  blower  is  to  be  pre- 
ferred.    The  cone  fan  shown  in  Fig.  20,  Part  I,  is  a  very  efficient 


Fi^.    14. 

form  and  may  be  used  in  a  wall  opening  as  there  shown  or  made 
double  and  enclosed  in  a  steel  plate  housing. 

Fan  Capacity.  The  volume  of  air  which  a  given  fan  will 
deliver  depends  upon  the  speed  at  which  it  is  run  and  the  friction 
or  resistance  through  the  heater  and  air  ways.  The  pressure 
referred  to  in  connection  with  a  fan  is  that  in  the  discharge  outlet 
and  represents  the  force  which  drives  the  air  through  the  ducts 
and  flues.  The  greater  the  pressure  with  a  given  resistance  in 
the  pipes  the  greater  will  be  the  volume  of  air  delivered,  and  the 
greater  the  resistance,  the  greater  the  pressure  requiied  to  deliver 
a  given  quantity. 

Fan  wheels  of  the  same  manufacture  are  usually  made  with 
a  constant  ratio  between  the  diameter  and  width,  although  special 


miATIXC    AM)   \KN'riI. ATIOX. 


foriu>  .lie  made  whoro  this  dcies  not  liold  trn(\  All  practical 
ilata  on  the  action  of  tans  is  hasi-il  mi  the  irsults  ot"  tests,  and 
friiin  ihe^r  llic  t'(>ll(>\\iiiL;"  relations  have  been  l'(»iiii(l  to  he  aj)|)rox- 
iniately  eorrei-t : 

(^1)  The  volnineot'  air  delivered  viiries  t/irr<-f/i/  :is  the  sj)eed 
of  the  fan,  that  is.  douhling  the  nniulu'r  of  revolutions  doubles 
the  volume  of  air  tlelivered. 

(2)  The  pressure  varies  as  the  square  of  the  speed,  for 
example,  if  the  speed  is  doubled  tlie  pressure  is  increased 
2  X  -  =  -4  times,  etc. 

(3)  The  power  required  to  run  the  fan  varies  as  the  cuhe 
of  the  speed;  again,  if  the  s[)eed  is  doubled  the  power  required  is 
increased  2  X  -  X  2  =  8  times. 

The  value  of  a  knowledge  of  these  relations  may  be  illustrated 
by  the  following  example. 

Sui)[)ose  for  any  reason  it  was  desired  to  double  the  volume 
of  air  delivered  by  a  certain  fan.  At  tirst  thought  we  might 
decide  to  use  the  same  fan  and  run  it  twice  as  fast ;  but  when  we 
come  to  consider  the  power  required  we  should  find  that  this 
would  have  to  be  increased  8  times,  and  it  would  j)robably  be 
much  cheaper  in  the  long  run  to  put  in  a  larger  fan  and  run  it  at 
lower  speed.  In  speaking  of  a  fan  as  a  4  or  5-foot  fan,  the 
diameter  of  the  propeller  wheel  is  meant,  but  if  we  say  an  80  or 
100-inch  fan  we  mean  the  height  of  casing  in  inches. 

It  has  been  found  in  practice  that  fans  of  the  blower  type 
having  curved  floats  operate  quietly  and  give  good  results  when 
run  at  a  speed  corresponding  to  |  ounce  pressure  at  the  disehaige 
outlet;  this  gives  a  speed  of  about  3G00  feet  per  minute  at  the 
circumference  of  the  wheel.  Higher  speeds  are  accomj)anied  with 
a  greater  expenditure  of  power  and  are  likely  to  produce  a  roaring 
noise  or  cause  vibr.ition.  A  inneh  lowo'  speed  does  not  ])rovide 
sufhcient  pressure  to  give  proper  control  of  the  air  distriI)ntion 
during  strong  winds.  The  following  table  gives  average  capacities 
for  various  sizes  of  fans  and  the  corresponding  horse-power  of 
engine  required.  If  an  electric  motor  is  used  iiiiiUii)ly  the  horse- 
power given  in  the  table  by  .13. 

This  is  done  because  we  can  never  tell  exactly  what  the  power 
required  will  be  and  it  is  well  to  have  an  excess  to  meet  any 


HEATING  AND  VENTILATION. 


23 


emergency  or  unlooked-for  conditions  which  may  arise.  In  the 
case  of  a  steam  engine  the  steam  pressure  may  l)e  raised  to  meet 
any  special  requirements  hut  a  motor  can  only  give  out  the 
original  power  for  whicli  it  was  designed. 

TABLE  III. 


Nominal    Size 

of  Fan.  Height 

of  Housing  in 

Inches. 

Diameter  of 

Fan  Wheel  in 

Inches. 

Width  of 

Housing  in 

Inches. 

Ordinary 
Speed    Giving 
i  Ounce  Pres- 
sure. 

Cubic  Feet  of  Air 

Delivered   per 

Minute. 

Horse- 
Power    of 

Engine  to 

Drive  the 

Fan. 

30 

18 

9 

870 

1000 

1 

"2 

40 

24 

12 

580 

1600 

1 

50 

30 

15 

465 

2600 

1 

60 

36 

18 

390 

4500 

2 

70 

42 

21 

333 

6000 

H 

80 

48 

24 

293 

8000 

01 

90 

54 

28 

260 

11000 

4 

100 

60 

32 

233 

12500 

4 

120 

72 

43 

195 

21500 

7 

140 

84 

48 

167 

28i)00 

9 

160 

96 

48 

147 

31800 

10 

108 

54 

130 

40400 

13 

120 

60 

117 

51000 

16 

Fan  Engines.  A  simple,  quiet  running  engine  is  desirable 
for  use  in  connection  with  a  fan  or  blower.  They  may  be  either 
horizontal  or  vertical  and  for  schoolhouse  and  similar  work  should 
be  provided  with  large  cylinders  so  that  the  required  power  may 
be  developed  without  carrying  a  boiler  pressure  much  above  30 
pounds.  In  some  cases  cylinders  of  such  size  are  used  that  a 
boiler  pressure  of  12  or  15  pounds  is  sufficient.  The  quantity  of 
steam  which  an  engine  consumes  is  of  minor  importance  as  the 
exhaust  can  be  turned  into  the  coils  and  used  for  heating  purposes. 
If  s[)ace  allows,  the  engine  should  always  be  belted  to  the  fan. 
Where  it  is  direct-connected,  as  in  Fig.  14,  there  is  likely  to  be 
troul)le  from  noise,  as  any  slight  looseness  or  pounding  in  the 
engine  will  be  communicated  to  the  air  ducts  and  the  sound  will 
be  carried  to  tlie  rooms  abov(\  Figs.  15  and  16  sliow  common 
forms  of  fan  engines.     The  latter  is  especially  adapted  to  this  pur- 


24 


11  FATING  AND  VENTl  LATIOX, 


ncjse   as   all    luMriiii^s   arc   oiicloscd   ami    j)i-(>ti'(ici|    froiu   dust    and 
<,'iil.      A  lioiizv)iilal  eiiniiu'  t'oi-  fan  use  is  shown  in   I'^ii;-.  17. 

Motors.      KU'i'trir    motors   aic   rsiicH-ially    adapted    for   use   in 


Fig.  15. 


connection  with  fans.     They  are  easily  controlled  by  a  switch  and 
starting  box  or  regulator.     The  motor  may  be  directly  connected 


HEATING  AND  VENTILATION. 


25 


to  the  fan  shaft  or  it  may  be  belted.     Fig.  18  shows  a  fan  with 
direct-connected  motor. 

Area  of  Ducts  and  Flues,  With  the  blower  type  of  fan  the  size 
of  the  main  ducts  may  be  based  on  a  velociy  of  1 200  to  1500  feet  per 
minute,  the  branches  on  a  velocity  of  1000  to  1200  feet  per  minute, 
and  as  low  as  600  to  800  feet  when  tlie  pipes  are  small.      Flue 


Fig.  16 


velocities  of  500  to  700  feet  per  minute  may  Ije  used  although  the 
lower  velocity  is  preferable.  The  size  of  the  inlet  register  should 
be  such  that  the  velocity  of  the  entering  air  will  not  exceed  about 
300  feet  per  minute.  Tlie  velocity  between  the  inlet  windows 
and  the  fan  or  heater  slionld  not  exceed  about  800  feet. 


•2U 


IIKATINC    AM)    \  KNIII.A'riON. 


Tlio  air  (hicls  and  llui's  aw  usually  made  of  galvanized  iron, 
the  ducts  luMug  run  at  the  hascnu'ul  cciliuiL^-.  No.  "J<>  and  "J'J  iron 
is  used  for  the  lari^or  sizes  and  l!4  to  i!S  for  the  smaller. 

He!^ul:ltin;jf  dampers  should  he  phieed  in  the  l)ran(hes  leading 
to  eaeh  line  for  inereasini;'  or  i-edueiii*^  the  air  sui)])ly  to  the  differ- 
ent rooms.  A«ljustable  deflectors  are  often  jjlaeed  at  the  fork  of 
a  pipe  for  ilie  same  ])nrpose.      One  of  these  is  shown  in  I'^Ilj".  10. 


1'IL^   17. 


Factory  Heating.  The  ai)plieation  of  foreed  blast  for  tlie 
warmin<^  of  factories  and  siiojjs  is  shown  in  Figs.  20  and  21,  The 
proportional  heating  surface  in  this  case  is  generally  expressed  in 
tlie  number  of  cubic  feet  in  the  building  for  each  linear  foot  of 
l-indi  steam  pijte  in  the  heater.  On  this  basis,  in  factory  prac- 
tice with  all  of  the  air  taken  from  out  of  doors,  theie  are  generally 
allowed  from  WO  to  150  cubic  feet  of  space  per  foot  of  pipe 
according  as  exhaust  or  live  steam  is  used  ;  live  steam  in  this  case 
indicating  steam  of  about  80  pounds  pressure.  If  practically  all 
of  the  air  is  returned  from  the  buildings  to  the  heater,  these  figures 
may  l)e  raised  to  aljout  140,  as  a  minimum  and  jjossibly  200  as  a 
maximum,  per  foot  of    pipe.      The  heateis  in  table  If  ma}'    be 


HEATING  AND  VENTILATION. 


changed  to  linear  feet  of  1  incli  pipe  by  multiplying  the   numbers 
in  column  three  (square  feet  of  surface)  by  three. 

EXAMPLES  FOR  PRACTICE. 

1.     A  machine  shop  100  feet  long  by  50  feet  wide  and  3 
stories,  each  10  feet  high,  is  to  be  warmed  by  forced  blast  using 


Fig.  18. 


exhaust  steam  in  the  heater.  The  air  is  to  be  returned  to  the 
heater  from  the  building  and  the  whole  amount  contained  in  the 
building  is  to  pass  through  the  heater  every  15  minutes,  what 
size  of  blower  will  be  recpiired  and  what  will  be  the  11. P.  of  the 
engine  required  to  run  it?  How  many  linear  feet  of  1  inch  j)ipe 
should  the  heater  contain  ? 

f90  inch  blower. 
Ans. -<'  1  H.P.  engine. 

1^1071  feet  of  ])ipe. 

2.     Find  the  size  of  blower,  engine  and  heater  for  a  factory 

200  feet  long  60  feet  wide  and  4  stories,  each  10  feet  high,  using 


lis 


iii:\ri\(;  and  ^•K^■'^II.ATI()^^ 


live  steam  at  80  pounds   |iivssuit'  in  the   lifatcr  ami  cliaiii;'!!!!;'  llio 
air  every  -'*  iniuutcs  Ity  takiii[^  in  ((tKl   air  trom  out  ol  doors. 

f  1 40  inch  blower. 
Ans.  }  !•  1 1.1'.  engine. 

[;5-2O0    feet' of  pipe. 

In  using  this  method  of  computation  judgment  must  be 
used  which  can  only  eonie  from  experience.  The  ligures  given 
are  for  average  conditions  of  construction  and  exi)osure. 

Double  Duct  System.  The  varying  cxixisures  of  the  rooms 
of  a  school  or  other  building  similarly  occupied  recpiire  that  more 
beat  shall  be  supplied  to  some  than  to  others.  Rooms  that  are  on 
the  south  side  of  the  building  and  exposed  to  the  sun  may  perhaps 
be  kept  perfectly  comfortable  with  a  supply  of  heat  that  will 
maintain  a  temperature  of  only  50  or  60  degrees  in  rooms  on  the 
opposite  side  of  the  building  which  are  exposed  to  high  winds  and  shut 

off  from  the  warmth  of  the  sun. 
♦  With  a  constant  and  equal 

air  supply  to  each  room  it  is 
evident  that  the  temperature 
must  be  directly  proportional  to 
the  cooling  surfaces  and  ex- 
posure, and  that  no  building  of 
this  character  can  be  properly 
heated  and  ventilated  if  the 
temperature  cannot  be  varied 
without  allecting  the  air  supply. 
There  are  two  methods  of 
overcoming  this  difficulty : 
The  older  arrangement  consists  in  heating  the  air  by  means 
of  a  primary  coil  at  or  near  the  fan  to  about  60  degrees,  or  to  the 
niininmm  temperature  required  within  the  building.  From  the 
coil  it  passes  to  the  bases  of  the  various  flues  and  is  there  still 
further  heated  as  required,  by  secondary  or  supplementary  heaters 
placed  at  the  base  of  each  flue. 

With  the  second  and  more  recent  method  a  single  lieater  is 
employed  and  all  of  the  air  is  heated  to  the  maximum  required  to 
maintain  the  desired  temperature  in  the  most  exposed  rooms, 
while  the  temperature  of  the  other  rooms  is  regulated  by  mixing 


HEATING  AND  VENTILATION. 


29 


with  the  hot  air  a  sufficient  volume  of  cold  air  at  the  bases  of  the 
different  flues.  This  result  is  best  accomplished  by  designing  a 
hot  blast  apparatus  so  that  the  air  shall  be  forced,  rather  than 


Fig.  20. 

drawn  through  the  heater,  and  by  providing  a  l)y-pass  through 
which  it  may  be  discharged  without  passing  across  the  heated 
pipes.     The  passage  for  the   cold  air  is  usually  made  above  and 


ao 


hi: Ai'iNi;  and  NKNrii.ATiox. 


sep«rate  from  the  heater  pipes  (see  F\^.  10.  Piirt  1.).  Extending 
innw  the  api):iratiis  is  a  (hnil>K'  system  (if  dmis,  usually  oi  ijalvaii- 
izeil  iron,  ai\(l  suspemlfd  iVoin  the  t'eilinn".  At.  the  hase  ol"  each 
flue  is  plaeed  a  niixiui;  dampt'r  \vhieh  is  controlled  hy  a  chain 
from  tiie  room  ahove  and  so  desii,Mied  as  to  admit  eitlier  a  full 
volume  of  hot  air,  a  tidl  volunk'  of  i-old  air  or  to  mix  them  in  any 


Fiir.  21. 


desired  proportion  without  affectinfr  the  rcsnltini^  total  v<dnnie 
delivered  to  the  room.  A  dami»er  of  this  form  is  shown  in  Fig.  22. 
Fig.  23  shows  an  arrangement  of  disc  fan  and  heater  where  the 
air  is  first  drawn  througli  a  tempering  coil,  then  a  portion  of  it 
forced  through  a  second  lieater  and  into  the  warm-air  pipes  while 
the    remainder  is  by-pjussed   under  the  lieater    into    the    cold-air 


HEATING  AND  VENTILATION. 


Bl 


pipes.     Mixing  dampers  ai-e  placed  at  the  bases  of  the  flues  as 
ah-eady  described. 

EXHAUST  VENTILAT80N, 

When  air  is  to  be  moved  against  a  very  slight  resistance,  as 
in  the  case  of  exhaust  ventilation,  the  disc  or  propeller  type  of 
wheel  may  be  used.  This  is  shown  in  different  foims  in  Figs.  24, 
25  and  26.  This  type  of  fan  is  light  in  co;istruction,  requires 
but  little  power  at  low 
speeds,  and  is  easily 
erected.  It  may  be  con- 
veniently placed  in  the 
attic  oi;  upper  story  of 
a  building,  where  it  may 
be  driven  either  by  a 
direct  or  belt-connected 
electric  motor.  Fig.  24 
shows  a  fan  equipped 
Avith  a  direct-connected 
motor,  and  Fig.  27 
the  general  arrangement 
when  a  belted  motor  is 
used.  These  fans  are 
largely  used  for  the  ^^<* 
ventilation  of  toilet  and 
smoking  rooms,  restau- 
rants, etc.  and  are  usually 
mounted  in  a  wall  open- 
ing, as  shown  in  Fig.  27. 
A  damper  should  always 
be  pi'ovided  for  shutting 
off  the  opening  when 
the  fan   is  not   in    use. 

The  fans  shown  hi  Figs.  25  and  26  are  provided  with  pulleys  for 
belt  connection. 

Fans  of  this  kind  are  often  conncnited  with  the  mam  vent 
flues  of  large  buildings,  such  as  schools,  halls,  churches,  theatres, 
etc.,    and    are    especially    adapt^    for    use    in    connection    with 


Fig.  22. 


32 


Ill-.ATIM^   AM)   NKN'ril.Al'ION', 


HEATING  AND  VENTILATION, 


33 


gravity  heating  systems.     Tlaey  ^re  usually  run  ^^jf^^^^ 


Ld    as  a  rule  are    placed    iu    positions   wlieie    an    engine    could 


Fig-  24. 
not  be  connected,  and  also  in  buildings  where  stea^n  pressure  is 

not  available.  , 

Table  IV  gives   the   air  delivery  per  minute  against  shglit 
resistance,  and  the  proper  size  of  motor  for  fans  of  the  disc  type. 

TABLE  IV. 


Diameter  of 
fan  in  inches. 


12 

18 
24 
30 
36 
42 
48 
54 
60 


Revolutions  per 
minute. 


1.000 
800 
500 
410 
380 
330 
280 
250 
230 


Cubic  feet  of  air 
delivered  per  minute. 

H.  P.  of 

Motor. 

600 

1 
4 

1,500 
2,300 

1 

2 
1 

3,500 
5,700 

1 

1.1, 

7,800 

9,900 

12,500 

2 
3 
3 

16,000 

5 

a  4 


Ill'.A'llM.   AM)   \  KNTILATION. 


HLECTRIC  HHATlNd. 

I'uU'ss  flfctricit V  is  produced  ;it  a  very  lnw  cost,  it  is  not 
COinnuMciallv  practical)!*'  for  licatiuLj  ri'sidcnccs  or  larq-i^  luiildiiin^s. 
Tlio  electrii-  hcau-r,  lu)\vevt'r,  lias  (inito  ;i  wide  lield  of  application 
ill  lieatiii'4  small  olliees,  hathioonis,  electric  cars,  etc.  It  is  a 
e(Miveiiient  method  of  warming-  rooms  on  cold  mornings  in  late 
sprini;  and  early  fall,  when  furnace  or  steam  heat  is  not  at  liand. 
It  has  the  especial  advantage  of    being    instantly  available,  and 


the  amount  of  heat  can  be  regulated  at   will.     The  lieaters  are 
perfectly  clean,  do  not  vitiate  the  air,  and  are  portable. 

Electric  Heat  and  Energy,  'i'he  commercial  unit  ff)r  elec- 
tricity is  one  watt  for  one  hour,  and  is  equal  to  3.41  15. 'I  .  L. 
Electricity  is  usually  sold  on  the  basis  of  1,000  watt  hours  (called 
Kilowatt-hours),  which  is  equivalent  to  3.410    1>.  T.  U.     A  watt. 


HEATING  AND  VENTILATION. 


35- 


as  we   liave   learned,  is  the   product  obtained  by  multiplying   a 
current  of  1  ampere  by  an  electro-motive  force  of  1  volt. 

From  the  above  we  see  that  the  B.  T.  U.  required  per  hour 
for  warming,  divided  by  3,410, 
will  give  the  Kilowatt-hours 
necessary  for    supplying   the 
required  amount  of  heat. 

Construction  of  Electric 
Heaters.  Heat  is  obtained 
from  the  electric  current  by 
placing  a  greater  or  less'  re- 
sistance in  its  path.  Various 
forms  of  heaters  have  been 
employed.  Some  of  the 
simplest  consist  merely  of 
coils  or  loops  of  iron  wire, 
arranged  in  ]3arallel  rows,  so 
that  the  current  can  be  passed 
througli  as  many  coils  as  are 
needed  to  provide  the  required  „.^ 

amount  of    heat.       In    other 

forms   tlie    heating  material  is  surrounded  with  fire-clay,  enamel 
or    asbestos,    and    in    some    cases    the    material  itself    has     been 


Fig.  27. 

such  as  to  give  considerable  resistance  to  the  current.  A  form 
of  electric  car  heater  is  shown  in  Fi";.  28.  Forms  of  radiators 
are  shown  in  Figs.  21,  22  and  23,  in  Part  I. 


A4» 


lll.AI'INi;    AM>   \  IlNTlI.A'riON. 


Connections  tor  Hlectric  Heaters.  Iln'  met  hod  <i|  wiiiiii^ 
for  t'K'rtrir  lioati'i-s  is  cssciit  ially  the  saiiic  as  for  lit^lils  which 
ri'ijuirt'  tho  same  ainomil  of  cuirciit.  A  constant  elccLio-inotive 
forci'  or  vohai^c  is  niainlaiiu'd  in  the  main  wiic  h'atlin<^  to  the 
Heaters.  A  ninch  less  voItaL;e  is  carried  on  the  retnin  wire,  and 
iIk' ourrent  in  passim;-  ihron^-h  the  lieater  from  the  main  to  the 
return,  dro]is  in  volla<;e  or  ])ressure.  'I'his  (hop  provides  the 
enerj^v  whiidi  is   transtornu-d    into   heat. 

'I'he  principle  of  electric  heatin<i^  is  mnidi  the  same  as  that 
involved  in  the  iion-sfravity  return  system  of  steam  heating-.  In 
that  system  the  pressure  on  liie  main  steam  pipes  is  that  of  the 
Uoiler.  while  that  on  the  return  is  much  less,  the  reduction  in 
pressure    occurriuL,^    in    the    passage    of    the    steam    throu^'h    the 


Fig.  28. 

i-adiators  ;  the  water  of  condensation  is  received  into  a  tank  and 
returned  to  the  boiler  hy  a  pump. 

In  a  system  of  electric  heating-  the  uuiin  wires  must  he  suiH- 
ciently  large  to  prevent  a  sensible  reduction  in  voltage  or  pressure 
between  the  generator  and  the  lieater,  so  that  the  pressure  in 
tliem  sliall  be  substantially  that  in  the  generator.  The  pressure 
or  \oliiige  in  the  ni;iiii  letuin  wiii;  is  also  constant,  but  very  low, 
and  the  generator  has  an  ofhce  similar  to  that  of  the  steam  pump 
in  the  system  just  described;  that  is,  of  raising  the  pressure  of 
the  return  current  up  to  that  in  the  main.  The  power  supplied  to 
the  generator  can  be  considered  the  same  as  the  boiler  in  the  first 
ca.se.  All  of  the  current  which  passes  from  the  main  to  the  return 
must  flow  through  the  heater  and  in  so  doing  its  pressure  or 
voltage  falls  from  that  of  the  main  to  that  of  the  return. 

From  the  generator  shown  in  Fig.  20,  main  andretinn  wires 


HEATING  AND  VENTILATION. 


37 


are  run  tlie  same  as  in  a  two-pipe  system  of  steam  heating,  and 
these  aie  proportioned  to  carry  the  required  current  without 
sensible  drop  or  loss  of  pressure.  Between  these  wires  are  placed 
the  various  heaters,  which  are  arranged  so  that  when  electric 
connection  is  made  they  diaw  the  current  from  the  main  and 
discharge  it  into  the  return  wire.  Connections  are  made  and 
broken  by  switches  which    take  the    place    of  valves    on    steam 

radiators. 

Cost  of  Electric  Heating.     The  expense  of  electric  heating 
must  in  every  case  be  great,  unless  the  electricity  can  be  supplied 


Yig.  20. 


at  an  exceedingly  low  cost.  Estimated  on  the  basis  of  present 
practice,  the  average  transformation  into  electricity  does  not 
account  for  more  than  4  per  cent  of  the  energy  in  the  fuel  which 
is  burned  in  the  furnace  ;  although  under  best  conditions  15  per 
cent  has  been  realized,  it  would  not  be  safe  to  assume  that  in 
ordinary  practice  more  than  5  per  cent  could  be  transformed  into 
electrical  energy.  In  heating  with  steam,  hot  water  or  hot  air, 
the  average  amount  utilized  will  probably  be  about  60  per  cent, 


38 


llKAriNi;    AM)    \  KN'I'lI.AriOX, 


s«>   tl);it    tlu'   i'X|)»Misf   (if    i'K'clric;il    licat  iiiLT    ''^   appiDxiiiuitcly    Troin 
1:2  Xo  1.")  tiuu's  ^rt'alor  tliaii  l>y  tlu'sc  met  liods. 

TEMPERATURE  REGULATORS. 

The    piiiu'ipal    systems    of    juitomatic     teni])t'raturo    control 


f^T-* 


FiL'.  :iO. 


Fig.  31. 


now  in  u.se  consist  of.  tlirce  essential  features  :  First,  an  air 
compressor,  reservoir  and  distriljiitino-  pipfs;  second,  thermo- 
stats, wiiicli  an;  placed  in  the  rooms  to  l)e  regulated  ;  and 
third,  special  diaphragm  or  pneumatic  valves  at  the  radiators. 
Tlie  air  rotnprcxKor  Ls  usually  operated  by  water  pressure  in 


HEATING  AND  VENTILATION. 


39 


small  plants  and  by  steam  in  larger  ones ;   electricity  is  used  in 
some  cases.      Fig.  30   shows  a  form  of  water  compressor.     It  is 
similar  in  principle  to  a  dircct-actirig  steam  pump,  in  wliich  water 
under  pressure  takes  the  place  of 
steam.      A    piston    in    the    upper 
cylinder  compresses  the  air,  which 
is  stored  in    a   reservoir  provided 
for  the  purpose.     When  the  pres- 
sure in  the  reservoir  drops  below 
a    certain    point,    the     compressor 
is  started  automatically,  and  con- 
tinues to  operate   until    the  pres- 
sure is  brought  up  to  its  working 
standard. 

A  thermostat  is  simply  a 
mechanism  for  opening  and  clos- 
ing one  or  more  small  valves,  and 
is  actuated  by  changes  in  the  tem- 
perature of  the  air  in  which  it  is 
placed.  Fig.  31  shows  a  thermo- 
stat ill  which  the  valves  are 
operated  by  the  expansion  and 
contraction  of  the  metal  strip  E. 
The  degree  of  temperature  at 
which  it  acts  may  be  adjusted  by 
throwing  the  pointer  at  the  bottom 
one  way  or  the  other.  Fig.  32 
shows  the  same  thermostat  Avith 
its  ornamental  casing  in  place. 
The  thermostat  shown  in  Fig.  33 
o[)erates  on  a  somewhat  different 
princi[)le.  It  consists  of  a  vessel 
separated  into  two  chambers  by  a 
metal  diaphragm.  One  of  these 
chambers  is  partially  filled  with 
a  liquid,  which  will  boil  at  a 
temperature  below  that  desired  in  the  room.  The  vapor  of  tlio 
li(|iiid  produces  considerable  pressure  at  the  normal  teinpcratui'e 


10 


lIKAl'lNc;    AM)    \  KNTILATIOX, 


of  the  i-oom,  and  a  slitjht  iiu'iciisc  of  luMt  ciowds  (iMMliapliriiuiii 
Dvor  and  ojUTati's  tlu'  small  valves  in  a  inaiiiifr  siiiiilar  lo  that 
(if  tlu'  iiu'tai    St  lip  in    tlu'   casi'    just    (Icsirilxd. 

Tlu'  i^'i'Mfial  i'oini  of  a  ifi<fj>/iniifni  vdlri'  is  shown  in  Fio',  84. 
I'hi'si'  ri'plaeo  the  usual  hand  valves  at  the  radiator.  'I'licy  are  simi- 
lar in  eonstrnelion  to  the  ordinaiv  Liflohe  or  aiiyle  valv(>,  except  the 
stem  sliiU's  up  and  down  instead  of  Itcini;  thri-adcd  and  running' 
in  a  nut.  'i'he  top  of  the  stem  connects  with  a  (lat  plate,  whicii 
rests  ajjj-ainst  a  ruhber  (haphraym.  The  valve  is  held  open  by  a 
spring,  as  shown,  and  is  closed  by  achnittino-  compressed  air  t<)  the 
space  alxive  the  (hai»hrai^ni. 

In  connecting-  up  the  system,  small  concealed  pipes  are  carried 


Fig.  33. 


from  the  air  reservoir  to  the  thei-inostat,  which  is  placed  upon  an 
inside  wall  of  the  room,  and  from  there  to  the  diaphragm  valve 
at  the  radiator.  When  the  temperature  of  the  room  reaches  the 
maximum  point  for  whicli  the  thermostat  is  set,  its  action  opens  a 
small  valve  and  admits  air  pressure  to  the  diaphragm,  thus  closing 
off  the  steam  from  the  radiator.  When  the  temj)erature  falls,  the 
thermostat  acts  in  tiie  opposite  mannei',  and  shuts  off  the  air  pres- 
sure from  the  diaphragm  valve,  and  at  the  same  time  opens  a 
small  exhaust  which  allows  the  air  above  tlu-  diaphragm  to  escape. 
The  pressure  being  removed  tiie  valve  opens  and  again  admits 
steam  to  the  radiator.  Thermostats  and  diaphi-agms  ar(;  also 
used  for  operating  mixing  dampers  in  a  similar  manner. 


HEATING  AND  VENTILATION. 


41 


HEATING  AND  VENTILATION. 
Various  Classes  of  Buildings. 

The  different  methods  used  in  heating  and  ventihition, 
together  with  the  manner  of  computing  the  various  proportions  of 
the  apparatus,  liaving  been  taken  up,  tlie  application  of  these 
systems  to  the  different  chisses  of  buildings  will  now  be  considered 
briefly. 

School  Buildings.  For  school  buildings  of  small  size,  the 
furnace  system  is  simple,  convenient  and  generally  effective.  Its 
use  is  confined  as  a  general  rule  to  buildings  having  not  more 


Fig.  34. 


than  eight  rooms.  For  large  ones  this  method  must  generally  give 
way  to  some  form  of  indirect  steam  system  with  one  or  more 
boilers,  which  occupy  less  space,  and  are  more  easily  cared  for  than 
a  number  of  furnaces  scattered  about  in  different  parts  of  the 
basement.  Like  all  systems  that  depend  on  natural  circulation, 
the  sup[)ly  and  removal  of  air  is  considerably  affected  by  changes 
in  the  outside  temperature  and  by  winds. 

The    furnaces    used    are    generally  built    of   cast  iron;    this 
material   being  durable,  and    easily   made    to    present    large   and 


42  IlKA'l'lNci   AM)   \  KNTILATION, 


eftVrtivf  lu'Mlint;  surf;u't'S.  To  :iil;i|il  tin*  liiincr  si/.cs  of  lioiisc- 
liealini;  fiiiii;u'»'S  to  scliools  ;i  iiiucli  laiL^cr  spine  must  he  provided 
lietweeii  tlie  hodv  and  the  easing',  to  lu'iinit  ;i  sidlicieiit  volume  of 
ail-  to  pass  to  the  roinns.  The  free  ait'a  of  the  air  passage  shoii hi 
be  sutlieient  to  allow  a  veloeity  of  abt)ul  400  feet  pei-  niimite. 

The  size  of  furnace  is  based  on  the  iuuouut  of  heat  h)st  by 
radiatitui  and  eonduetion  through  walls  and  windows  jjIiis  that 
carried  awav  bv  air  passing  up  the  ventilating  Hues.  These 
quantities  may  be  computed  by  the  usual  methods  for  "loss  of 
heat  by  condmtiou  thiough  walls,"  and  "heat  required  for 
ventilation."  With  more  legular  and  skillful  attendance,  it  is  safe 
to  assume  a  higher  rate  of  combustion  in  schoolhouse  heaters  than 
in  those  used  for  warming  residences.  Allowing  a  niaxinnuu 
combustion  of  6  pounds  of  coal  per  hour  p^-r  scpuire  foot  of  grate, 
and  assuming  that  8,000  B.  T.  U.  per  pound  are  taken  up  by  the 
air  passing  over  the  furnace,  we  have  6  X  8,000  =  48,000  B.T.U. 
fiu-nished  per  hour  per  square  foot  of  grate.  Therefore,  if  we 
divide  the  total  B.  T.  U.  required  for  both  warming  and  ventilation 
by  48,000,  it  will  give  us  the  necessary  grate  surface  in  square  feet. 
It  lias  been  found  in  practice  that  a  furnace  with  a  fire-pot  82  inches 
in  diameter,  and  having  ample  heating  surface,  is  capable  of  heat- 
ino-  two  50-pupil  rooms  in  zero  weathei'.  The  sizes  of  ducts  and 
flues  may  be  determined  by  rules  already  given  under  furnace  and 
indirect  steam  heating. 

The  indirect  gravity  system  of  steam  heating  comes  next  in 
cost  of  installation.  One  important  advantage  of  this  system 
over  funiace  heating  comes  from  the  ability  to  place  the  heating 
coils  at  the  base  of  the  flues,  thus  doing  away  with  horizontal 
runs  of  air  pipe,  which  are  required  to  some  .extent  in  furnace 
heating.  The  warm-air  currents  in  the  flues  are  less  affected  by 
variations  in  the  direction  and  force  of  the  wind  where  this  con- 
struction is  possible,  and  this  is  of  much  importance  in  exposed 
locations.  The  method  of  su])plying  cold  air  to  the  coils  or 
heaters  is  important,  and  should  be  carefully  worked  out  in  the 
manner  previously  descril^ed.  ^Mixing  dampers  for  regulating  the 
temperature  of  the  rooms  should  be  jtiovided  for  each  flue.  The 
effectiveness  of  these  dampers  will  depend  largely  upon  their 
construction,  and    they    should    be    made    tight    against    c(jld-air 


HEATING  AND  VENTILATION.  « 


leakage  by  covering  the  surfaces  or  flanges  against  wh.ch  they 
close  witl,  some  form  of  asbestos  felting.  Both  mlet  and  outlet 
gratings  slionkl  be  provided  with  adjustable  dampers  One  of 
the  disadvantages  of  this  system  is  the  delivery  of  all  the  hea  to 
the  room  from  a  single  point,  and  this  not  always  in  a  position 
to  give  the  best  results.  The  outer  walls  are  thus  left  unwarmed, 
except  as  the  heat  is  diffused  throughout  the  room  by  an-  currents. 
When  there  is  considerable  glass  surface,  as  in  most  of  our 
modem  schoolrooms,  draughts  and  currents  of  cold  au-  are 
frequently  found  ahmg  the  outside  walls. 

A  very  satisfactory  arrangement  is  the  use  of  mdirect  heaters 
for  warming  the  air  needed  for  ventilation,  and  the  placing  of 
direct  radiation  in  the  rooms  for  heating  purposes.     The  genera 
construction  of  the  indirect  stacks  and  flues  may  be  the  same,  but 
the  heating  surface  can  be  reduced,  as  the  air  in  this  c,«e  must 
be  raised  only  to  70  or  75  degrees  in  zero  weather;  the  heat  to 
offset  that  lost  by  conduction,  etc.,  through  walk  and  windows 
being  provided  by  the  direct  surface.     The  mixing  dampers  are 
also  oLted,  and  the  tempemture  of  the  room  ^'^'^""'^,^1 
opening  or  closing  the  steam  valves  on  the  direct   cods,  which 
Zy  b!  done  either  by  hand  or  automatically.     The  direct-heat- 
ing   surface,    which   is   best   made   up  of  lines  of     |-inch  pipe, 
should  be  placed    along   the  outer  walk    beneath  the  windows^ 
This  supplies  heat  where  most  needed,  and  does  away  with  tlie 
tendency  to  draughts.     In  mild  weather,  during  the  spring  and 
f!n   the  indirect  lieaters  may  prove  sufficient  for  both  ventilation 

""'*  There  direct  radiation  is  placed  in  the  rooms,  the  quantity  of 
heat  supplied  is  not  affected  by  varying  wind  conditions,  as  is  the 
ease  in  indirect  heating.  Although  the  air  supply  may  be  redu  ed 
a  Tines,  the  heat  quantity  is  not  changed.  Direct  rad.at.on  ha. 
the  disadvantage  of  a  more  .r  less  unsightly  m—^^J^ 
architects  and  owners  often  object  to  the  running  of  mans  or 
risers  through  the  rooms  of  the  building.  A"'  ™1™''  " 
always  be  provided  with  drip  conneetions  carried  to  a  sink  oi  diy 

well  in  the  basement.  ,     .    p  i     •   „„..  jo 

When  circulation  coils  are  used,  a  good  method  of  drainage  is 

to  carry  separate  returns  from  each  coil  to  the  basement,  and  place 


n 


lIKATINc;    AND  V  KNTI  I.A  TlOX. 


I>^3J.S^£  3N/JVJN  OJ.  X£nVHX3 


HEATING  AND  VENTILATION.  45 


tlie  air  valves  iu  the  drops  just  below  the  basement  ceiling,      A 
check    valve    should    be    placed    below    the    water    line    in    each 

return. 

Tiie  fan  or  blower  system  for  ventilation  with  direct  radiation 
in  the  rooms  for  warming,  is  considered  to  be  one  of  the  best 
possible  arrangements. 

In  designing  a  plant  of  tliis  kind  the  main  heating  coil  should 
be  of  sufficient  size  to  warm  the   total    air  supply  to  70  or  75 
degrees  in  the  coldest  Aveather,  and  the  direct  surface  should  be 
proportioned  for  heating  the  building  independently  of  the  indirect 
system.     Automatic  temperature  regulation  sliould  be  used  in  con- 
nection with  systems  of  this  kind  l)y  placing  pneumatic  valves  on 
the  direct  radiation.     It  is  customary  to  carry  from  3  to  8  pounds 
pressure  on  the  direct  system  and  from  8  to  15  on  the  main  coil 
depending  upon  the  outside  temperature.     The  foot-warmers,  ves- 
tibule and   office  heaters  should  be  placed  on  a  separate  line  of 
pipmg.  with  separate  returns  and  trap,  so  that  they  can  be  used 
independently  of  the  rest  of  the  building  if  desired.    Where  there 
is  a  large  assembly  hall  it  should  be  arranged  so  that  it  may  be 
both  warmed  and  ventilated  when  the  rest  of  the  building  is  shut 
off.     This  may  be  done  by  a  proper  arrangement  of  valves  and 
dampers.     When  different  parts  of  the  system  are  run  on  different 
pressures  the  returns  from  each  should  discharge  through  separate 
traps  into  a  receiver  having  connection  with  the  atmosphere  by 
means  of  a  vent  pipe.     Fig.  35  shows  a  common  arrangement  for 
the  return  connections  in  a  combination  system  of  this  kind.     The 
different  traps  discharge  into  the  vented  receiver  as  shown,  and 
the  water  is  pumped  back  to  the  boiler  automatically  when  it  rises 
above  a  given  level  in  the  receiver,  a  pump  governor  being  used 
to  start  and  stop  the  pumps  as  required. 

A  water  level  or  seal  of  suitable  height  is  maintamed  in  the 
main  returns  by  placing  the  trap  at  the  required  elevation  and 
bringing  the  returns  into  it  near  tlie  bottom  ;  a  balance  pipe  is  con- 
nected with  the  top  for  equalizing  the  pressure  the  same  as  m  the 
case  of  a  pump  governor.  Sometimes  a  fan  is  used  with  the  heating 
coils  placed  at  the  base  of  the  flues,  instead  of  in  the  rooms.  Where 
this  is  done  the  radiating  surface  may  be  reduced  about  one-half. 
This  system  is  less  expensive  to  install,  but  has  the  disadvantage 


40  llKATLNc;   AM)   VKNTI1>.VTU)X. 


i)t  ri'iiioN  ini;  till'   luMtiiiiL,^  siiifiuo    Iroin    lln'   coM    walls   where  it  is 
most  lU'i'tUd. 

Churches.  Clmii'lu's  may  Kc  waniud  hy  runiacrs,  indirect 
st«Mm,  or  1)V  nu'ans  ol  a  Ian.  I'or  small  buildiiin's  ilie  Inrnacc  is 
mort'  ((imnionh^  used.  This  a|>|»aralus  is  the  sim|)l('st di'  all  and 
is  fompanitivcly  inexpensive.  llt'iU  may  he  i^MMU'i-ated  (ini(d<ly, 
;ind  Avlien  the  lires  are  no  lon<^er  lUH'ded  they  niay  lie  allowed  to 
go  out  without  danger  of  damage  to  any  pait  of  the  sy-'^tem  from 
freezing. 

It  is  not  usually  necessary  that  the  heating  apparatus  be  large 
enough  to  warm  the  entire  building  at  one  time  to  70  degrees  with 
fretjuent  ehangeof  air.  if  the  building  is  thoroughly  wainied  before 
oceu]>anev.  either  by  rotation  or  by  a  slow  inward  movement  of 
outside  air,  tiie  ehapel  or  Sunday-sehool  room  may  ])e  shut  oH"  until 
near  the  close  of  the  service  in  the  auditorium,  when  a  portion  of  the 
warm  air  may  be  turned  into  it.  Wlien  the  service  ends,  the 
switch  damper  is  opened  wide,  and  all  oi"  the  air  is  dischai-ged  into 
the  Sunday-school  room.  The  position  of  the  warm-air  registers 
will  depend  somewhat  upon  the  construction  of  the  building,  but 
it  is  well  to  keep  them  near  the  outer  walls  and  the  colder  parts 
of  tlie  room.  Large  inlet  registers  shoidd  be  placed  in  the  floor 
near  the  entrance  doors,  to  stop  cold  drafts  from  blowing  up  th(^ 
aisles  when  the  doors  are  opened,  and  also  to  be  used  as  foot- 
warmers. 

( "eiling  ventilators  are  generally  provided,  but  should  be  no 
laro-er  than  is  necessary  to  remove  the  pi-odiu;ts  of*  condjustion 
from  the  gaslights,  etc.  If  too  large,  nnicli  of  the  warmest  and 
purest  air  will  escape  through  them.  'J'he  mam  vent  flues  shotdd 
be  placed  in  or  near  the  floor  and  should  be  connected  witli  a  vent 
shaft  leading  outbound.  This  flue  should  be  provided  with  a  small 
stove  or  flue  heater  made  especially  for  this  purpose.  In  cold 
weather  tlie  natural  draft  will  be  found  suflicient  in  most  ca.ses. 
The  same  general  rules  follow  in  tlie  case  of  iiulirect  steam  as 
have  Ix-en  described  for  furnace  heating.  The  stacks  are  placed 
beneath  the  registers  or  flues  and  mixing  damperft  i)rovided.  If 
there  are  large  windows,  flues  should  Ije  arranged  to  open  in  the 
wiiulow  sills  so  tliat  a  sheet  of  warm  air  may  be  deliv(;red  in  front 
of  tlie  windows,  to  counteract  the  effects  of  cold  down  drafts  from 


HEATING  AND  VENTILATION. 


47 


the  exposed  glass.  These  flues  may  usually  be  made  3  or  4  inches 
m  depth,  and  should  extend  the  entire  width  of  the  window. 
Sm.all  rooms,  such  as  vestibules,  librar}^,  pastor's  room,  etc.,  are 
usually  heated  with  direct  radiators.  Rooms  which  are  used  dur- 
ing the  week  are  often  connected  with  an  independent  heater  so 
that  they  may  be  warmed  without  lunning  the  large  boilers,  as 
would  otherwise  be  necessary. 

When  a  fan  is  used  it  is  desirable,  if  possible,  to  deliver  the  air 
to  the  auditorium  through  a  large 
number  of  small  openings.  This 
is  often  done  by  constructing  a 
shallow  box  under  each  pew,  run- 
ning its  entire  length,  and  con- 
necting it  with  the  distributing- 
ducts  by  means  of  a  pipe  from 
below.  The  air  is  delivered  at  a 
low  velocity  through  a  long  slot, 
as  shown  in  Fig.  36. 

The  warm-air  flues  in  the 
window  sills  should  be  retained 
hut  may  be  made  shallower  and 
tlie  air  forced  in  at  a  high 
velocity. 

Halls.  The  treatment  of  a 
larsfe   audience  hall    is   similar   to 

that  of  a  church,  and  is  usually  warmed  hi  one  of  the  three  ways 
already  described.  Where  a  fan  is  used  the  air  is  commonly 
delivered  through  wall  registers  placed  in  part  near  the  floor  and 
partly  at  a  height  of  7  or  8  feet  above  it.  They  should  be  made 
of  ample  size,  so  that  there  will  be  freedom  from  draughts.  A  part 
of  the  vents  should  be  placed  in  the  ceiling  and  tlie  remainder 
near  the  floor.  All  ceiling  vents  both  in  halls  and  churches  sliould 
be  provided  Avith  dampers,  having  means  for  holdmg  them  in  any 
desired  position.  If  indirect  gravity  heaters  are  used,  it  will 
generally  be  necessary  to  place  heating  coils  in  the  vent  flues  for 
use  in  mild  weather;  but  if  the  fresh  air  is  supj)lied  by  means  of  a 
fan  there  will  usually  be  pivssure  enough  in  the  room  to  force  the 
air  out  without  tlie  aid  of  other  means.     When  the  vent  air  ways 


Fio-.  36. 


48  lIKATINt;    AM)    \  KN  Tl  I,  A  I'lON. 

art-  I'l'sii  ic'tt'il,  or  tlic  iilr  is  im|n'(li'(l  in  aii\-  \\;i\.  electric  veiililatiiii^ 
tans  are  often  nsed.  These  *j^\\v  t'speeially  jjjood  res-ults  in  waiiner 
weather,  when  natiiial  \ cut ihitinii  is  shinojsli.  The  temperature 
may  he  reL,''ilate<l  I'ithei'  hy  iisiuM-  (he  (h)iihle  duet  system  or  l)y 
shutting  olT  or  luiiiiiiLr  tni  a  ^-realer  or  less  minihcr  of  sections  in 
tlie  main  heater.  Alter  an  audience  hall  is  ouic  warmed  and  iilh-d 
with  people,  vi'ry  little  ht'at  is  re([uirt'd  to  Uee[)  it  eomrortahle,  even 
in  the  coldest  weather. 

Theaters.  In  desii^niuL;"  lusting  and  ventilatiug  systems  for 
thealci-s.  a  wide  I'xperieiiee  and  the  greatest  car(!  arcf  iieeessary  to 
Si-eure  the  l>est  results.  A  theater  consists  of  thi'ee  parts:  the 
l)t»dy  of  the  liouse,  or  auditorium  ;  the  stage  and  dressing-rooms ; 
and  the  foyer,  lobhies,  eorritlors,  stairways  and  offices.  Theaters 
are  usually  located  in  cities,  and  surrounded  witli  other  buildings 
on  two  or  more  sides,  thus  allowing  no  direct  coniiection  by 
windows  with  the  external  air;  for  tiiis  leasoii  artificial  means  are 
necessary  for  ])rovi(ling  suitable  ventilation,  and  a  forced  circula- 
tion by  means  of  a  fan  is  liie  only  satisfactoiy  means  of 
accomplishing  this.  It  is  usually  advisable  to  cretite  a  slight 
excess  of  pressure  in  the  auditorium,  in  oidei-  that  all  openings 
shall  allow  for  the  discharge  rather  than  the  inwaid  leakage  of 
air. 

The  general  and  most  approved  method  of  air  disti-ibutiou  is 
t<t  force  it  int(r  closed  spac(\s  beiu'ath  the  auditorium  and  balconv 
floors,  and  alhjw  it  to  discharge  upward  thi-ough  small  openings 
amf)ng  the  seats.  One  of  the  best  methods  is  through  chair-legs 
of  special  latticed  design,  which  are  placed  over  suitahle  openings 
in  the  floor;  in  this  way  the  air  is  delivered  to  tlie  room  in  small 
streams  at  a  low  velocity  without  drafts  or  cui-reuts.  The  dis- 
charge ventilation  should  he  lai'gely  through  ceiling  vents,  and 
this  may  he  assisted  if  necessaiy  by  the  use  of  v(!iitilating  fans. 
Vent  openings  should  also  be  j)rovided  at  the  rear  of  the  balconies 
either  in  the  wall  or  ceiling,  and  thes(;  should  be  coniu'cted  with 
an  exhaust  fan  either  in  the  bjusement  or  attic,  as  is  most 
convenient. 

The  close  seating  of  the  occupants  produces  a  large  amount 
of  ardmal  heat,  which  usually  increases  the  temperature  from  6  to 
10  degrees,  or  even   more;  so  that  in  considering  a  theater  once 


HEATING  AND  VENTILATION.  49 


filled  and  thoroughly  warmed  it  becomes  more  of  a  question  of 
cooling  than  one  of  warming  to  produce  comfort. 

Office  Buildings.      This  class  of  buildings  may  be  satisfac- 
torily warmed  by  direct  steam,  hot  water,  or  where  ventilation  is 
desired  by  the  fan  system.      Probably  direct  steam   is  used  more 
frequently    than   any  other    system    for    this    purpose.     Vacuum 
systems  are  well  adapted  to  the  conditions  usually  found  in  this 
type  of  building,  as  most  modern  office  buildings  have  their  own 
light    and    power  plants,    and    the    exhaust    steam    can    be   thus 
utilized  for  heating  purposes.     The  piping  may  be  either  single 
or  double.     If  the  former  is  used  it  is  better  to  carry  a  single 
main  riser  to    the    upper  story  and  run  drops  to  the  basement, 
as  by  this  means  the  flow  of  steam  and  water  are  in  the  same 
direction  and  much  smaller  pipes  can  be  used  than  would  be  the 
case  if  risers  were  carried  from  the  basement  upward.     Special 
provision  must  be  made  for  the  expansion  of  the  risers  or  drops  in 
tall   buildings.     They  are   usually   anchored    at    the   center    and, 
allowed  to  expand  in  both  directions.      The  connections  with  the 
radiators  nuist  not  be  so  rigid  as  to  cause  undue  strains  or  lift  the 
radiators  from  the  floor. 

It  is  customary  in  most  cases  to  make  the  connections  with 
the  end  farthest  from  the  riser ;  this  gives  a  length  of  horizontal 
pipe  which  has  a  certain  amount  of  spring,  and  will  care. for  any 
vertical  movement  of  the  riser  which  is  hkely  to  occur.  Forced 
hotrwater  circulation  is  often  used  in  connection  with  exhaust 
steam.  The  water  is  warmed  by  the  steam  in  large  heaters, 
similar  to  feed-water  heaters,  and  circulated  through  the  system 
by  means  of  centrifugal  pumps.  This  has  the  usual  advantage 
of  hot  water  over  steam,  inasmuch  as  the  temperature  of  tlie 
radiators    may   be    regulated    to    suit    the    conditions   of    outside 

temperature. 

Apartment  Houses.  These  are  warmed  by  furnaces,  direct 
steam  and  hot  water.  Furnaces  are  more  often  used  in  tlie  smaller 
houses,  as  they  are  cheaper  to  install,  and  require  a  less  skilful 
attendant  to  operate  them.  Steam  is  probably  used  more  than 
any  other  system  in  blocks  of  larger  size.  A  well-designed  single 
pipe  connection  with  automatic  air  valves  dripped  to  the  base- 
ment is  probably  the   most    satisfactory  in    this    class    of    work. 


oO 


llKATl-NG  A.ND   \  ENTILATIO.N. 


IN'oplf  will)  :ui'  inon'  tir  h'ss  imraiuiliar  with  stcaiii  systems  ar(3 
apt  tn  nvorlook  oiu'  »>r  till-  \al\('s  in  sliutiiiii;-  olT  (H-  luniiiiL,^  on 
iitoam.  ami  where  duIv  «'Iic  NaUc  is  used,  llic  (lilliciilt  \   arisiiitj"  liom 


FiK.  37. 


tills  is  avoided.  Wlicre  pct-cdck  air  valves  aie  used  they  are 
/»ften  left  open,  ihioiii^di  earelessness,  and  the  autoinatie  valves, 
unless  dripjiid,  are  likely  to  give  more  or  less  tronble. 

Greenhouses  anrl  eonservatoiies  are  heated  in  some  cases  by 


HEATING  AND  VENTILATION. 


51 


steam  and  in  others  by  hot  water,  some  florists  preferring  one  and 
some  the  other.  Either  system  when  properly  designed  and  con- 
structed should  give  satisfaction,  although  hot  water  has  its  usual 
advantage  of  a  variable  temperature.  The  methods  of  piping  are 
in  a  general  way  like  those  already  described,  and  the  pipes  may 
be  located  to  run  underneath  the  beds  of  growing  plants  or  above 
as  bottom  or  top  heat  is  desired.  The  main  is  generally  run  near 
the  upper  part  of  the  greenhouse  and  to  the  furtherest  extremity 
in  one  or  more  branches,  with  a  pitch  upward  from  the  heater  for 
hot  water  and  witli  a  pitch  downward  for  steam.      The  principal 


Fiir.  38. 


radiating  surface  is  made  of  parallel  lines  of  li  inch,  or  larger, 
pipe,  placed  under  the  benches  and  supplied  by  the  return  current. 
Figs.  37,  38  and  39  show  a  common  method  of  running  the  piping 
in  greenhouse  work.  Fig.  37  shows  a  plan  and  elevation  of  the 
building  with  its  lines  of  pipe,  and  Figs.  38  and  39  give  details  of 
the  ]5ipe  connections  of    the    outer   and   inner   groups   of    pipes 

respectively. 

Any  system  of  piping  which  gives  free  circulation  and  which 
is  adapted  to  the  local  conditions  should  give  satisfactory  results. 


0-2 


IlKATl.NG  AM)   \  I^NTIl.ATION. 


Tilt"  nuliiiiiiii,'  suifarr  iiiiiy  lu'  (•(uiipntrd  tVoiii  ilic  riiU's  iiliviuly 
given.  As  ihf  avi'iaj^o  i,neeiili()iise  is  conipost'd  almost  entirely 
of  gla^.s  we  may  for  purposes  of  ealculation  consider  it  such,  and 
if  we  divide  ihe  total  exposed  surface  by  4  we  sliall  i,'et  practically 
the  sftme  result  as  if  wr  assumed  a  liral  loss  of  8;')  B.  T.  U.  j)er 
square  fot't  of  surface  ju'i-   lioui  and    ;iii    eflieicuev  of   :*>;'><>  I'..  T.  U. 


¥\ir.  :]n. 


for  the  heating  coils;  so  that  we  may  say  in  general  that  the 
square  feet  of  radiating  surface  required  equals  the  total  exposed 
surface  divided  by  4  for  steam  coils  and  by  2.5  for  hot  water. 
These  results  shouUl  Ik-  increased  fiom  10  to  20  per  cent  for  ex- 
posed locations. 

CARE  AND  MANAGEMENT. 

The  care  of  furnaces,  hot-water  heateis  and  steam  boilers  has 
been  discussed  in  connection  with  the  design  of  these  different 
systems  of  heating,  and  need  not  be  rei)eated.  The  management 
of  the  heating  and  ventilating  systems  in  large  school  buildings  is 
a  matter  of  much  importiince,  esj)eciHlly  in  those  using  a  fan 
system ;  to  ol^taiu  the  best  results  as  much  depends  upon  the  skill 
of  the  f»f>erating  engineer  as  upon  that  of  the  designer. 

Beginning  in  the  boiler  room,  he  should  exercise  special  care 


HEATING  AND  VENTILATION.  53 

in  tlie  management  of  his  fires,  and  the  instruction  given  in 
"  Boiler  Accessories  "  shoukl  be  carefully  followed ;  all  flues'  and 
smoke  passages  should  be  kept  clear  and  free  from  accumulations 
of  soot  and  ashes  by  means  of  a  brush  or  steam  jet.  Pumps  and 
engine  should  be  kept  clean  and  in  perfect  adjustment,  and  extra 
care  should  be  taken  when  they  are  hi  rooms  through  which  the 
air  supply  is  drawn,  or  the  odor  of  oil  will  be  carried  to  the 
rooms.  All  steam  traps  should  be  examined  at  regular  intervals 
to  see  that  they  are  in  working  order,  and  upon  any  sign  of 
trouble  they  should  be  taken  apart  and  carefully  cleaned. 

The  air  valves  on  all  direct  and  indirect  I'adiators  should  be 
inspected  often,  and  upon  the  failure  of  any  room  to  heat  properly 
the  air  valve  should  first  be  looked  to  as  a  probable  cause  of  the 
difficulty.  Adjusting  dampers  should  be  placed  in  the  base  of 
each  flue,  so  that  the  flow  to  each  room  may  be  regulated  inde- 
pendently. In  starting  up  a  new  plant  the  system  should  be  put 
in  proper  balance  by  a  suitable  adjustment  of  these  dampers,  and 
when  once  adjusted  they  should  be  marked  and  left  in  these 
positions.  The  temperature  of  the  rooms  should  never  be  regu- 
lated by  closing  the  inlet  registers.  These  should  never  be 
touched  unless  the  room  is  to  be  unused  for  a  day  or  more. 

In  designing  a  fan  system  provision  should  be  made  for  "  air 
rotation  "  ;  that  is,  the  arrangement  should  be  such  that  the  same 
air  may  be  taken  from  the  building  and  passed  through  the  fan 
and  heater  continuously.  This  is  usually  accomplished  by  closing 
the  main  vent  flues  and  the  cold-air  inlet  to  the  building,  then 
opening  the  class-room  doors  into  the  corridor  ways,  and  drawing 
the  air  down  the  stairwells  to  the  basement  and  into  the  space 
back  of  the  main  heater  through  doors  provided  for  this  purpose. 
In  warming  up  a  building  in  the  morning  this  should  always  be 
practiced  until  about  fifteen  minutes  before  school  opens.  The 
vent  flues  should  then  be  opened,  doors  into  coi-ridoi's  closed,  and 
cold-air  inlets  opened  wide,  and  the  full  volume  of  fresh  air  taken 
from  out  of  doors. 

At  night  time  the  dampeis  in  the  main  vents  shoukl  be 
closed,  to  prevent  the  warm  air  contained  in  the  building  from 
escaping.  The  fresh  air  should  be  delivered  to  the  rooms  at  a 
temperature  of  from  70  to  75  degrees,  and  this  temperature  must 


f.4 


lIKATlNt.    AND    \  I'A'I'I  L  A  TloN, 


l»o  olttaiiuMl  l)v  inojuT  use  of  tin-  sluil-ulT  \;il\(s,  thus  niiiuiiiti;  a 
•^rt'atrr  or  If-s  niimlKT  ol"  st'i-tidiis  on  llic  main  heater.  A  liLthi 
e\|HTifiu-i'  will  show  the  iMiLcincer  lu)\v  many  sections  to  i  aiiy  lor 
ilitYeitMit  tlei,n-ees  of  mitsiiU'  teui|ierat ni\'.  A  dial  tlieinionu'liT 
sh'Hild  he  j>laeetl  in  tlie  ni;iin  warm-air  tluel  near  the  fan,  so  that 
the  leini'ejaiure  of  the  air  clelivored  to  the  i-ooms  can  be  .eiujily 
note<l. 


Fig.  40. 

The  i-xhanst  steam  from  the  engine  and  pnmps  shouhl  })e 
turned  uit<»  the  main  heater;  tliis  will  su[)ply  a  greater  number  of 
seetions  in  mild  weather  tlian  in  cold,  owing  to  the  less  ra{)id 
eondensation. 

STEAM  FITTING. 

In  order  to  design  a  system  intelligently  the  engineer  should 
have  some  knowletlge  of  the  methods  of  actual  construction,  the 
tools  used.  eti'.  It  is  enstomary  wliert^  a  piece  of  work  is  to  be 
done  to  send  a  su{)ply  of  pipe  and  fittings  to  the  building  some- 


0 


Fi^r.  41. 


wliat  greater  than  is  refjuired,  and  the  workman  after  receiving 
the  plans  of  construction,  which  show  the  loctation  an<l  sizes  of  the 
various  pipes  to  be  erected,  makes  liis  own  measuiements,  cuts 
the  pipes  to  the  proper  length  at  the  building,  threads  them  and 
screws  them  into  place. 


HEATING  AND  VENTILATION. 


55 


The  tools  belonging  to  this  trade  consist  of  tongs  or  wrenches 
for  screwing  the  pipe  together,  cutters  for  cutting,  taps  and  dies 
for  threading  the  pipe,  and  vises  for  holding  it  in  position  while 
cutting  or  threading.     A  great  variety  of  tongs  and  wrenches  are 


Fisr.  42. 


to  be  found  on  the  market.  For  rapid  work  no  tool  is  superior  to 
the  plain  tongs  (shown  in  Fig.  40),  especially  for  the  smaller 
sizes  of  pipe.  The  alligator  wrench  (shown  in  Fig.  41)  is  used 
in  a  similar  manner  on  light  work  and  where  the  pipes  turn  easily. 


Fig.  43. 

For  large  pipe,  chain  tongs  of  some  pattern  are  the  best,  and  maybe 
used  with  little  danger  of  crushing  the  pipe.  (See  Fig.  42.)  A 
form  of  wrench,  known  as  the  Stilson,  one  form  of  which  is  shown 
in  Fig.  43,  is  widely  used.    The  wrenches  or  tongs  which  are  used 


Fig.  44. 


for  turning  the  pipe,  in  most  cases,  exert  more  or  less  lateral 
pressure,  and  if  too  great  strength  is  applied  at  the  handles  there 
is  a  tendency  to  split  the  pipe.  The  cutter  ordinarily  employed 
for  small  pipe  consists  of    one  or  more  sharp-edged  steel  wheels. 


5»5 


IKAI'lNii    AM)    \  KNTlLAriON. 


whii-ii  nrv   helil  in  ;iii  iuljustaliK'  t'liiiiu'  (^st-c    l<'ii;.    II  )  ;  llu-  cutting 

lH'in«;  |K'rf(>niio»l   1)V   applyiuj^  pri'ssmr  niid    if\ oh  iiiiic    it  iiiimiul 

tlu'  l'ilH>.      A  sei'tiiui  of  oiu*  of   tlu>  ciitiiiiL;'  \vlictls   is  shown   in 

Fiij.   45.      With  this   tool    the   cutting'   is   ;ii-i-oni|ihshf(l    hy  simply 

orowdini,'  the  uu't;il  to  one  side, 

anil  hence  hnirs  of  «'oiisidcr;dile 

size  will  l)e  fornu-d  on   the  out-    /      /^S^PV^^X 

sitle     ;ind     inside    of     the    j)ipe. 

I'siiallv  tlie   outside  liinr  must 

l)e  removed  1)V  lilinLT  In'fore  the 

jiijx^  can  he  tlni-aded.     The  inside 

burr    fonns  a  irreat  obstruction  Fig-  45. 


Fiff.  47. 


to  the  flow  of  steam  or  water,  and  should  in  every  case  be  removed 
by  tlie  use  of  the  reamer.     There  are  many  forms  of  reamers  for 


F\^.  46. 


use  in  various  cases;  one  of  tlie  simplest  is  showii  in  Fig.  46. 

Tl»e  ratchet  drill  is  another  tool  often  used,  and  is  especially 
useful  i?i  drilling  holes  in  pipes  or  fittings  after  the  work  is  in 


HEATING  AND  VENTILATION. 


57 


place.  One  of  these  is  shown  in  Fig.  47 
vise  used  for  holding  the  pipe  while  cut- 
ting and  threading  is  shown  in  Fig.  48. 
The  combination  vise  is  shown  in  Fig.  49. 
The  dies  for  threading  the  pipes  are 
usually  of  a  solid  form,  each  die  fitting 
into  a  stock  or  holder  with  handles.  (See 
Fig.  50.)  The  cutting  edges  of  the  dies 
should  be  kept  very  sharp  and  clean,  other- 
wise perfect  threads  cannot  be  cut.  In 
cutting  threads  on  wrought  iron  pipe,  oil 
should  always  be  used,  which  will  tend  to 
prevent  heating  and  crumbling,  and  make 
the  work  easier.  In  erecting  pipe  great 
care  should  be  taken  to  preserve  the  proper 
pitch  and  alignment,  and  to  ap[)ear  well 
the  pipes  should  be  screwed  together  until 


A  common  form  of 


Fig.  ^9. 

no  threads  are  in  sight.  Every  joint  should  be  screwed  from 
6  to  8  complete  turns  for  sizes  2  inches  and  under  and  from  8 
to  12  turns  for  the  larger  sizes,  otherwise  there  will  be  danger 
of  leakage. 

In  screwing  pipes  togetlier,  red  or  white  lead  is  often  used. 


58 


11EATIN(;    AND   \  KNIM  I.A  TION. 


It  will  'jfiMuMullv  l>t'  toiiiul  llmt  liiistH'd  (ir  soiiu'  l;()i>(1  liiliiifatiug 
oil  will  lu*  iHiu.illy  valuaMf.  If  possihlc,  tlic  work  should  be 
ainmijftHl  so  that  it  can  bo  made  Uj>  with  rigiit  and  left  eoui)lin^s 
or  other  tittinirs. 


Fiff.  50. 


Packed  joints,  especially  unions,  are  objectionable  and  likely 
to  leak  after  use.  Flange-unions  with  copper  gaskets  should  be 
used  on  heavy  work.  Good  workmansliip  in  pipe-fitting  is  shown 
by  the  perfection  with  which  small  details  are  executed,  and  poor 
workmanship  in  any  of  the  particulars  mentioned  may  defeat  the 
perfect  operation  of  the  best  designed  jjlant. 


EXAfllNATION   PAPER. 

HEATING  AND  VENTILATION 
PART  III. 


HEATING  AND  VENTILATION. 


Read  carefully  the  following  instructions:  Place  your  name  and  full 
address  at  the  head  of  the  pajjer.  Any  cheap  light  paper  like  the  sample 
previously  sent  you  may  be  used.  Do  not  crowd  your  work,  but  arrange  it 
neatly  and  legibly.  Work  out  in  full  the  examples,  showing  each  step  in  the 
work,  and  mark  all  answers  plainly,  "Ans."  Do  not  copy  answers  froin  the 
instruction  paper ;  use  your  own  words.  After  completing  the  work  add  and 
sign  the  following  statement : 

I  hereby  certify  that  the  above  work  is  entirely  my  own. 

(Signed) 


1.  A  main  heater  contains  1,040  square  feet  of  heating  sur- 
face made  up  of  wrought  iron  pipe,  and  is  used  in  connection  with 
a  fan  which  delivei'S  528,000  cubic  feet  of  air  per  hour,  Tlie 
heater  is  20  pipes  deep  and  has  a  free  area  between  the  pipes  of 
11  square  feet.  If  air  is  taken  at  zero,  to  what  temperature  will, 
it  be  raised  with  steam  at  5  pounds  pressure  ? 

Ans.  140°. 

2.  A  nine-foot  fan  running  at  180  revolutions  delivers 
40,000  cubic  feet  of  air  per  minute.  If  the  fan  is  speeded  up  to 
169  revolutions,  and  an  electric  motor  substituted  for  the  engine, 
what  will  be  the  rating  of  the  required  motor? 

3.  What  precaution  must  be  taken  in  connecting  the  radi- 
ators in  tall  buildings. 

4.  Give  the  size  of  heater  from  Table  II,  which  will  be 
required  to  I'aise  (172,000  cubic  feet  of  air  per  hour,  from  10°  be- 
low zero  to  90°,  with  a  steam  pressure  of  20  pounds.  If  the  air 
quantity  is  raised  to  840,000  cubic  feet  per  hour  through  the  same 
heater,  what  will  be  the  resulting  temperature  with  all  other  con- 
ditions the  same  ? 

.Ans.  8r).5°. 

5.  A  fan  running  at  150  revolutions  produces  a  pressure 
of  4  ounce.  If  the  s})eed  is  increased  to  210  i-evolutions,  what 
will  be  the  resulting  pi'essure? 

6.  A  certain  fan  is  delivering  12,000  cubic  feet  of  air  per 
minute,  at  a  speed  of  200  revolutions.  It  is  desired  to  increase 
tlie  amount  to   18,000    cubic   feet.     What   will   be   the  required 


IIKATINU   AM)   \  KNI'II.A'I'ION. 


sju't'tl?      It"  tlu-  oiii^^inal  pow*'!-  inniinMl  to  luii  tlic  laii  \\;is    I    II.  1'., 
\vli:it   will  1)0  tli«'  liiiiil  power  dm'  to  tlu'  iiuToasi'([  sin^d? 

7.  What  si/.t'  fail  will  lu'  nMpiiicd  to  supiily  a  sdiooiliouse 
liaviiiLT  •>'•<>  pupils,  it  carh  is  to  in'  pro\i(lc(t  willi  ;),(H)()  ciihic;  feet 
ot"  air  per  hour?  What  s[)f(Ml  of  fan  will  Iw  i('(|uii<'(l.  and  what 
11.   P.  of  iiii^int'/ 

8.  What  ad\  autaijft's  has  tin-  plniuui  UH'tliodof  \  i-iililatioii 
o\«'r  till-  «>xhaust  lucthod? 

9.  A  church  is  to  he  warmed  and  ventilated  by  means  of  a 
fan  and  heater.  The  air  supply  is  to  be  300,000  cubie  feet 
per  hour.  The  heat  loss  through  \valls  and  windows  is  200,000 
1'..  r.  r..  when  it  is  lo^  below  zi'io.  How  many  square  feet  of 
heating  surface  will  l)e  required,  and  how  many  rows  of  pipe  deep 
must  thi-  lii-attM-  be  with  steam  at  o  pounds  pressure? 

Alls.  14  rows. 
!<•.  A  schoolhouse  recpiiring  (')()0,0<)0  cubic  feet  of  air  per 
hour  is  to  be  sup[)lied  with  a  cast  iron  sectional  heater.  How 
many  square  feet  of  radiating  surface  will  be  lequired  to  raise  the 
air  from  10°  Ijelow  zero  to  70°  above,  with  a  steam  pressure  of  20 
pounds :'  ^^f 

Ans.  #>H^quare  feet. 

11.  What  velocities  of  aii-llow  in  the  main  duct  and 
braneiies  are  commonly  used  in  connection  with  a  fan  s\stem  ? 

12.  A  main  heater  is  to  be  designed  for  use  in  connection 
witii  a  fan.  How  many  scjuare  feet  of  radiation  will  be  retjuired 
to  warm  1,000.0(10  cubic  feet  of  air  per  hour,  from  a  temperature 
of  10°  below  zero  to  70°  above,  with  a  steam  pressure  of  20 
pounds  and  a  velocity  of  800  feet  [ler  minute  between  the  })ipesof 
the  heater?      How  many  lows  of  pipe  deep  must  the  heater  be? 

Ans.  882  square  feet. 

13.  State  ill  a  biief  iiiaiiiier  the  (;sseiitial  parts  of  a  system 
of  aut^jiiiatic  tempeiatui'e  control. 

14.  Wiiat  advantage  does  an  indirect  steam  heating  system 
have  over  furnace  heating  in  sclioolhouse  work  ? 

lo.  The  air  in  a  restaurant  kitchen  is  to  be  clianged  every 
10  minutes  by  means  of  a  disc  fan.  The  room  is  20  X  30  X  10. 
Give  size  and  speed  of  fan  and  H.  P.  of  motor. 


HEATING  AND  VENTILATION.  63 

16.  What  forms  of  heating  are  best  adapted  to  the  warming 
of  apartment  houses  ? 

17.  Give  an  approximate  method  for  finding  the  heating  sur- 
face required  for  greenhouses,  both  for  steam  and  hot  water. 

18.  How  does  the  cost  of  electric  heating  compare  with  that 
by  steam  and  hot  water  ? 

19.  Describe  briefly  the  construction  of  an  electric  heater, 
and  the  principle  upon  which  it  works. 

20.  A  school  building  of  4  rooms  is  to  be  supplied  with 
600,000  cubic  feet  of  air  per  hour.  The  heat  loss  from  the  build- 
ing is  300,000  B.  T.  U.  per  hour  in  zero  weather.  Give  the  square 
feet  of  grate  surface  required  in  the  furnaces. 

21.  What  is  a  double  duct  system  as  applied  to  forced  blast 
heating?     What  are  its  advantages? 

22.  What  is  a  thermostat  ?  Give  the  principles  upon  which 
two  different  kinds  operate. 

23.  Describe  briefly  the  connections  to  be  made  in  a  system 
of  electric  heating.  In  what  way  do  they  correspond  to  the  pip- 
ing in  a  system  of  steam  heating  ? 

24.  State  certain  points  to  be  observed  in  the  introduction 
of  air  for  the  ventilation  of  churches  and  theatres. 

25.  A  shop  100  feet  long,  50  feet  wide  and  5  stories,  each 
10  feet  high,  is  to  be  warmed  b}^  forced  blast  using  steam  at  80 
pounds  pressure.  The  full  amount  of  air  passed  through  the 
heater  is  to  be  taken  from  out  of  doors,  and  the  entire  air  of  the 
buildino;  changed  3  times  an  hour.  Give  linear  feet  of  1  inch 
pipe  required  for  heater,  and  size  of  fan  and  engine. 

(  1,666  feet  of  pipe. 
Ans.  }  5-foot  fan. 

(  4  H.  P.  engine. 

26.  In  what  cases  would  you  use  a  disc  fan  in  preference  to 
a  blower? 

27.  Tlie  heat  loss  from  a  room  is  12,000  B.  T.  U.  per  hour. 
How  many  Kilov/att-hours  will  be  required  to  furnish  the  neces- 
sary heat  ? 

28.  What  is  one  of  the  best  systems  for  the  heating  and 
ventilation  of  school  buildings  of  large  size  ? 


64  IIKAI'INC    AM)   \  KN  Tll.A'noX. 


29.  Whiit  form  of  licatiiii,'  systtMu  would  you  rccoiunicnd 
for  a  f»mr-rooiu  school? 

l\0.  A  fiU'ti>rv  "JnO  feet  loui^'  by  oO  I't'ct  wkIc  lias  two  stories, 
each  \0  feet  \n\^\\.  Dwrli  lloor  is  to  liavr  a  separate'  fau  and 
heater,  but  tiie  fans  are  to  be  driven  by  the  same  electric  motor. 
The  lower  floor  is  to  be  supplii'd  with  air  from  out  of  doors  and 
is  to  have  a  complete  chann'e  of  air  every  'JO  miuules.  On  llie 
upper  tloor  the  air  is  to  1k'  returned  to  the  heater  from  the  loom, 
and  tiie  entire  contents  is  to  ])ass  throuj^li  the  heater  every  15 
minutes.  Exhaust  steam  is  to  be  used  in  both  heaters.  Give 
sizes  of  funs,  heaters  and  nu)tor. 

.         \  Lower  floor  3.^-foot  fan. 
I  I7pper  floor  4-foot  fan. 


PLUMBING 


PART      I. 


INSTRUCTION     PAPER 


AMERICAN      SCHOOL      OF      CORRESPONDENCE 

[CHABTKKED    BV    THE    COMMONWEALTH     OF    MASSACHUSETTS] 

'      BOSTON,     MASSACHUSETTS 
U.   S.   A. 


Prepared  By 
ChARLKS    L.    HlBBARD.    M.K., 

OF 

S.  Homer  Wooijhridge  Company, 
Heating,  Ventilation  and  Sanitary  Engineers. 


PLUMBING. 


PLUMBING  FIXTURES. 

Bath  Tubs.  There  are  many  varieties  of  bath  tubs  in  use  at 
the  present  time,  ranging  from  the  wooden  box  lined  witli  zinc  or 
copper  which  was  in  common  use  a  number  of  years  ago  and  is 
still  to  be  found  in  the  old  houses,  to  the  finest  crockery  and 
enameled  tubs  which  are  now  used  in  the  best  modern  plumbing. 
In  selecting  a  tub  we  should  choose  one  with  as  little  woodwork 
about  it  as  possible.  Those  lined  with  zinc  or  copper  are  hard  to 
keep  clean  and  are  liable  to  leak  and  are,  therefore,  undesirable 
from  a  sanitary  standpoint.  The  plain  cast  iron  tub,  painted,  is 
the  next  in  cost.     This  makes  a  serviceable  and  satisfactory  tub  if 


kept  painted;  it  is  used  quite  extensively  in  asylums,  hospitals, 
etc.  One  of  this  type  is  shown  in  Fig.  1.  These  are  sometimes 
galvanized  instead  of  being  painted. 

The  "steel-clad"  tub  shown  in  Fig.  2  is  a  good  form  for  a 
low-priced  article.  This  tub  is  formed  of  sheet  steel  and  has  a 
lining  of  copper.  This  form  is  light  and  easy  to  handle  ;  it  is  an 
openlaxture  the  same  as  the  cast  iron  tub  and  requires  no  casing. 
It  is  provided  with  cast  iron  legs  and  a  wooden  cap.  Probably 
the  most  common  form  to  be  found  in  the  average  house  at  the 
present  time  is  the  porcelain  lined  iron  tub  as  shown  in  Fig.  3. 


I'l.lMI'.INC. 


Tliis  lia>  a  >nio<itli  iiiU'iior  liiiisli  and  is  easily  kept  clean.  It  will 
not,  liowt'ver,  stand  the  hard  iisaL>e  of  those  al)ove  di'serihed  as 
the  linini;-  is  likidy  to  erat'k  if  struck  by  any  hai-d  substance. 

In  Kii^-.  4  is  shown  a  eioekeiy  or  porcelain  (uh  ai-ran<^e(l  for 
needle  and  siiower  batlis.  This  is  a  most  sanitary  article  in  every 
respect  and  reipiires  no  woodwork  of  any  kind;  heiiit;'  made  of  one 


piece,  there  is  no  chance  for  dirt  to  collect.  It  is  a  heavy  lul)  and 
requires  great  care  in  handling.  This  material  is  very  cold  to  the 
t-ouch  until  it  has  become  thoi-oughly  warmed  by  the  hot  water. 
Fi'^f.  •"  shows  a  seat  bath  and  Fio-.  (I  a  foot  bath,  both  of  which  are 


very  convenient   and   should  be   placed    in    all    well   ecjuijiped   l)ath 
Itxuiis  if  tin-  expetise  does  not  i)rohiV)it  theii'  use. 

Water  Closets.  Tliere  is  a  great  variety  of  water  closets 
from  which  to  cheese,  many  operating  upon  the  same  principle 
but  varving  slightlv  in    form   and    finish.      The  best  are   made  of 


PLUMBING. 


porcelain,  the  bowl  and  trap  being  in  one  piece  without  corners  or 
crevices  so  that  they  are  easily  kept  clean.  The  to})  of  the  bowl 
is  provided  with  a  wooden  rim  and  cover.  The  general  arrange- 
ment of  seat  and  flushing  tank  is  sliown  in  Fig.  7.  A  section 
through  the  bowl  is  shown  in   Fig.  8.      This  type  is  known  as  a 


Fig.   4. 


syphon  closet,  and  those  made  on  this  principle  ai-(^  probably  the 
most  satisfactory  of  any  in  present  use.  Tliey  are  made  in  differ- 
ent forms  by  various  manufacturers  but  each  involves  the  prin- 
ciple which  gives  it  its  name.  Water  stands  in  the  bottom  as 
shown,    thus    forming    a    seal    against    gases    from     the    sewer. 


i\  I'l.i  .mi'.im;. 

W'lii'ii  liu-  «.'li)St>t  is  lliislift],  \\;itfi-  nislirs  down  the  |>i|n'  :iii<l  lills 
the  small  cliamluT  ;il  llir  it-ar  which  ilisi-harLCt's  in  a  jet  at  tlu' 
lK>ttt>m  as  shown  hy  tlu-  arrow.  Tlu'  syphon  action  thns  set  up 
(liaws  ihc  futii-c  cniiiciits  of  llic  liowl  over  into  the  soil  pipe.  In 
the  nieantiine  a  j»art  of  the  water  iroiu  the  tank  lills  the  hollow 
rim   of  the   htiwl    and   is   discluuired    in  a  thin   stream   aronnd    the 


Fij:.  5. 


^TT 


Fig.  0. 


Fijr.  7. 


entire  perimeter  which  thoroughly  washes  the  inside  of  the  l;ow'l 
eacli  time  it  is  fluslied.  Fig.  9  shows  a  form  called  the  "  wash- 
out "elo.set.  In  this  case  the  whole  of  the  water  is  discharged 
througli  the  flushing  rim  l)ut  with  greater  force  at  the  rear  wdiich 
waslies  the  contents  of  the  upper  howl  into  the  lower  which  over- 
flows into  the  soil  pipe.  This  is  a  good  form  of  closet  and  is 
widely  used.     A  .similar    form,   but    without  tlie    upper    howl  Lj 


PLUMBING. 


7 


shown  in  Fig.  10.  This  is  known  as  the  "wash  down"  closet 
and  operates  in  the  manner  already  described.  The  water  enters 
the  bowl  through  the  flushing  rim  and  discharges  its  contents  by 


Fiff.  8. 


Fig:.  •>• 


•overflowing  into  the  soil  pipe.      This  is  a  simple  foini  of  closet 
and  easily  kept  clean. 

One  of  the  simplest  closets  is  the  ''  hoppei- "'  shown  in  Fig.  11. 
This  consists  of  a  plain  bowl  of  porcelain  or  cast  iron  ta2)ering  to 


Fig.  10. 


Fig.  11. 


an  outlet  about  4"  in  diameter  at  the  l)ottom.  It  is  connected 
directly  with  the  soil  jjipe  as  shown.  The  trap  may  be  placed 
either  above  the  floor  oi-  below  as  desired.  They  are  provided 
with  a  flushing  rira  at  the  top  similar  to  that  already  described. 
This  type  of  closet  is  the  cheapest  but  at  the  same  time  the  least 
satisfactory  of  any  of  the  cjifl:erent  kinds  shown. 


8  iM,r.MniX(;. 

1 1  is  soiiu'tiiiu's  (I('siial)lt'  to  \)\;ico  a  closet  in  a  lotMLioii  where 
iliorc  wouUl  ho  thm<,'er  of  trt'e/iiii]^  if  the*  usual  forui  of  flushini^ 
tank  was  used.  Fit;.  1-  shows  an  airan^fcnu'iit  which  may  be 
used  in  a  case  of  this  kind.  'V\n-  \alve  and  watei-  connections  are 
placed  holow  the  frost  line  and  a  pipe  not  shown  in  the  cut  is 
earned  up  to  the  riui  of  the  l)o\\l.      Whcnthe  rim  is  shut  down  the 


Fi.r.  12. 


valve  is  opened  h\-  means  of  the  chain  attached  to  it  and  Avater 
flows  through  the  bowl  while  in  use.  When  released,  the  weight 
on  the  lever  closes  the  valve  and  raises  the  wooden  rim  to  its 
original  po.sition.  Any  water  which  remains  in  the  flush  pipe  is 
drained  to  the  soil  pipe  through  a  small  drip  jiipe  which  is  seen  in 
the  cut. 

Urinals.  A  coniiuon  form  of  urinal  is  shown  in  l*'ig.  1;>. 
The  partitions  and  slab  at  the  back  are  either  of  slate  or  marble 
and  tlie  bowl  of  porcelain.  They  may  be  flushed  like  a  closet. 
Fig.  14  shows   a  section    through    the    bowl    and    indicates    the 


PLUMBING. 


manner  of  flushing,  partly  through  the  rim  and  partly  at  the  back. 
The  trap  or  seal  is  shown  at  the  bottom.  Anptiier  form  is  sliown 
in  Fig  15  In  this  case  tlie  bowl  remains  partly  filled  with 
water  wliich  forms  a  seal  as  shown.  It  is  flushed  both  through 
the  rim  and  the  passage  at  the  back.  In  action  it  is  the  same  as 
the  svphon  closet  shown  iu   Fig.  8  and  the  bowl  is  drained  each 


Fig.  13. 


Fig.  14. 


time  it  is  flushed,  l)ut  immediately  fills  with  water  to   the  level 

indicated.  ., 

An  automatic  flushing  device  is  illustrated  m  Fig.  lb.      When 

the  water  line  in  the  tank  reaches  a  given  level,  the  float  lever 
releases  a  catch  and  flushes  the  urinal.  The  intervals  of  flushing 
can  be  regulated  by  adjusting  the  cock  shown  in  the  ndet  ])ipc. 
near  the  bottom  of  the  tank. 

\  simple  form  of  urinal  commonly  used  in  schools  and  public 
buildings  is  shown  in    Fig.  17.     This   is    flushed   by  means    of 


10 


I'l.r.MlilN'G. 


small  streams  of  wiitiT  wliioh  an;  dis- 
I'harjred  tlirougli  I  he  j)erforat('(l  jnpe 
iicai-  (lu!  top  of  the  slab  at  the  back 
and  run  down  in  ;i  thin  slicct  to  the 
l»'utt(M-  at  the  l)()ttoin. 

Lavatories.  Howls  and  lava- 
tories can  be  had  in  almost  any  form. 
Fig.  18  shows  a  simple  coi'iicr  lava- 
toiy,  made  of  porcelain  and  provided 


Fiu.   1^. 


Fig.   17. 


Fiff.   16. 

with  hot  and 
cold  water  fau- 
cets. It  has  an 
overflow,  shown 
l»y  the  small 
openings  at  the 
l)ack  and  a  rub- 
ber plug  for  clos- 
ing the  drain  at 
the  bottom. 

The  lavatory 
shown     in    Fig. 

19  is  provided 
with  marble 
slabs  and  is  more 
expensive.    Fig. 

20  shows  a  sec- 
tion through  the 
bowl.  The 
waste  pipe  is  at 
the  back,  which 


PLUMBING. 


11 


brings  the  plug  and  chain  well  out  of  the  way.  A  pattern  still 
more  elaborate  is  shown  in  Fig.  21,  and  a  section  through  the 
bowl  in  Fig.  22.  The  waste  pipe  plug  in  this  case  is  in  the 
form  of  a  hollow  tube  and  acts  as  an  overflow  when  closed  and 
as  a  strainer  when  open.      It  is  held  open  by  means  of  a  slot  and 


l^ll^^l* 


-J_ 


Fig.  18. 


Fig.  19. 


pin  near  the  top.  Fig.  23  shows  a  bowl  so  arranged  that  either 
hot,  cold  or  tepid  water  may  be  drawn  through  the  same  opening 
which  is  placed  well  down  in  the  bowl  where  it  is  out  of  the  way. 


Fig.  20. 


Sinks.  Sinks  are  made  of  plain  wood,  and  of  wood  lined 
with  sheet  metal,  such  as  copper,  zinc  or  galvanized  iron.  They 
are  also  made  of  sheet  steel,  cast  iron,  either  plain,  galvanized  or 
enameled,  and  of  soapstone  and  porcelain.  Each  has  its  advan- 
tages   and    disadvantages.       The    wooden    sink  is  liable  to  leak. 


1-2 


n.l  MUINC. 


aiul  is  (lilVuuIi  {o 
k  e  r  p  tlioioii^Hilv 
cloan.  Tlif  liiieil 
sink  is  most  satis- 
tacioiy  wIkmi  new, 
l»iit  hoK's  aiv  «juite 
o  airily  cut  or 
punclioil  tlin)ug;h 
the  lining  and  it 
then  becomes  very 
objectionable  from 
a  sanitary  stand- 
point as  the  greasy 
water  antl  vege- 
table matter  whicli 
woiks  through  the 
opening  causes  the 
woodwork  to  decay 
mpidly  and  to  give 
off  in  the  process 
a  t'as  which  is  not 


Ficr.    21. 


only  unhealtiiful  but  tends  to  destroy  the  lining  of  the  sink  from 
the  undei-side  so  that  its  destruction  is  rapid  after  a  leak  is  once 

started.  The  cast 
iron  sink  is  satisfac- 
tory. The  appearance 
is  improved  })y  galvan- 
izing, l)ut  this  soon 
wears  off  on  the  in- 
side. Enameled 
sinks  are  easily-  kept 
clean  but  likely  to 
become  cracked  or 
broken  from  Ijard 
usage  or  from  ex- 
tremes of  hot  or  cold ; 
the  porcelain  sink  has 
the  same   defects; 


Fijr.  22. 


PLUMBING. 


13 


they  are  both  however  well  adapted  to  2)laces   where   tliey  will 
receive  careful  usage. 

Taking  all   points  into  consideration  the  soapstone  sink  may 
perhaps    be  considered   the   most   satisfactory   for  all-around  use. 


Fig.  23. 

It  will  not  absorb  moisture  ;  is  not  affected  ])y  tlie  action  of  acids; 
oil  or  grease  will  not  enter  the  pores  and  it  is  not  injured  by  hot 
water  nor  liable  to  crack. 

Fig.  24  shows  the  ordinary  cast  ii'on  sink,  made  to  be  set  in 
.a  vrooden  casing  ;  this  is  not  to  be  recoan mended  however,  and  it  is 


Fie-.  24. 


much  better  to  support  them  upon  iron  brackets  or  legs.  Fig.  25 
shows  an  enameled  sink  mounted  in  this  way.  A  porcelain  sink 
with  dish  racks  is  shown  in  Fig.  26.  This  is  a  good  form  for  a 
pantry  sink  which  is  used  only  for  washing  cutlery,  glassware, 


14 


riA:.MliIN(i. 


cixw-kery.  t'tr..  and  is  not  suliit'clt-tl  lo  liaid  iisatj^t'.  A  slop  sink  is 
shown  ill  Kiij.  "JT.  i'liis.  as  will  l»e  noUccil,  is  jhon  idrd  with  an 
t'Xtni  lai-«j;t'  waste  iii[n'  and  (rap  to  ]»r«n'(Mit  (don^in^-.  Tlu'sc  sinks 
aiv  Miadi-  of  cast  iron  w  itii  ditVcifnl  iinislics  and  of  porcelain. 

Set    tul>s    tor   lanndry    nsc    are  'made  of  soajjslone,   slate,  east 


Fijr. 


iron  (^enameled  oi-  (j;alvani/,ed)  and  of  j>orcelain.  Wliat  lias  ])eeu 
said  ill  le^Mi'd  to  kitelien  sinks  apjilies  e(|ually  well  in  tliis  case. 

A  set  of  ('hanieled  tnljs  is  shown  in  Fij^.  '2H. 

Traps.  A  trap  is  a  loop  or  watei' seal  })laced  in  a  j>ipe  to  pi"e- 
veiit  the  Lrases  from  the  drain  or  sewer  fif»m  passing  uj»  throuo-h  the 
waste  pipes  of  the  fixtures  into  the  looms.  A  common  fr)rni  made 
lip  of  cast  iron  pilte  and  known  as  a  '•running  traj)  "  is  shown  in 
Fig.  29.      A  trap  of  this  foini  is  placed  in  the  main  drain  pij)e  of  a 


PLUMBING. 


15 


building  outside  of  all  the  connections  to  2)ievent  gases  from  tlie 
main  sewer  or  cesspool  from  entering  the  building.  A  removable 
cover  is  placed  on  top  of  the  trap  to  give  access  for  cleaning. 

The  floor  trap  shown  in  section  in  Fig.  30  is  made  both  of 
brass  and  of  lead.  It  is  commonly  used  for  kitchen  sinks  and  is 
placed  on  the  floor  just  beneath  the  fixture.  It  is  provided 
with  a  removable  trap  screw  or  clean-out  for  use  when  it  is  desired 


-^ 


Fi"-.  26. 


to  remove  grease  oi'  sediment  from  the  interior.  Fig.  31  shows  a 
common  form  for  lavatories,  which  consists  simpl}'  of  a  loop  in  the 
waste  pipe.  These  are  usually,  made  of  brass  and  nickle  plated 
when  used  with  open  fixtures.  A  trap  for  similar  purposes  is 
shown  in  Figs.  32  and  33. 

Figs.  34  and  35  show  a  form  known  as  the  centrifugal  trap  on 
account  of  the  rotary  or  whirling  motion  given  to  the  water  by 
the  peculiar  arrangement  of  the  inlet  and  outlet.  This  motion 
carries  all  solid  })articles  to  the  outside  and  discharges  them  with 
the  water,  thus  keeping  the  trap  clear  of  sediment.  Where  there 
is  likely  to  be  a  large  amount  of  grease  in  the  water  as  in  the  case 
of  waste  from  a  hotel  or  restaurant  it  becomes  necessary  to  use  a 
special  form  of  separating  trap  to  jirevent  the  waste  pipes  from  becora- 


16 


PI.UMIUNG. 


iiig  clogged.  A  L^'n-ast^  tia[)  dt'sigiu'd  foi-  (his  |)iiijH)se  is  sliown  in, 
Fig.  3(5.  Its  artion  is  ivatlily  si-i'ii  as  iho  fatty  matter  will  be 
separated,  lirst  by  droppiiitj^  into  a  lari^e  body  of  cold  water  and 
then  K'ing  driven  against  the  centi-r  paitition  l)efore  an  outlet  can 
be  gjiined.  The  grease  then  rises  to  the  surface  where  it  cools 
and  i-an  then  1k»  easily  removed  as  often  as  lu'cessary. 

Sometimes  a  cfUar  or  Itasement  is  drained  into  a  sewer  which 


Fi},r.  21. 


is  liable  to  be  filled  at  high  tide  or  from  other  causes  and  a 
8|)ecial  trap  or  che(.-k  must  be  used  to  prevent  the  cellar  from 
becoming  flooded.  Such  a  trap  is  sliown  in  Fig.  37.  When 
water  flows  in  from  below,  the  float  lises,  and  the  rid)ber  lim 
l»ressing  against  the  valve  seat  prevents  any  passage  through  the 
trap;  the  cut  shows  the  valve  closed  by  the  action  of  high  water. 
Tanks  or  cisterns  for  flushing  closets  or  other  fixtures  are 
usually  made  of  wood  and  lined  with  zinc  or  copper.  These  are 
generally  placed  iiLside  a  finished  casing.    A  common  form  is  shown 


PLUMBING. 


17 


ill  Fig  38.  The  arrangement  of  valves  for  supplying  water  to 
the  tank  and  for  flushing  the  fixtures  is  shown  in  Fig.  39.  The 
larcre  float  or  ball  cock  regulates  the  flow  of  water  mto  tlie  tank 
irom  the  street  main  or  house  tank.      When  the  water  in  the  tank 


Fig.  28. 


falls  below  a  certain  level  the  float  drops  and  opens  a  valve,  thus 
admitting  more  water,  and  closes  again  when  the  tank  is  filled. 
The  closet  is  flushed  by  pulling  a  chain  attached  to  the  lever  at 
tlje  right  which  opens  the  valve  in  the   bottom  of  the   tank   and 
admits  water  to  the  flushing  pipe.      In  this  form  the  valve  remains 
open  only  while  the  lever  is  held  down  by  the 
chain,  the  weight  on  the  other  end  of  the  lever 
closing  the  valve  as  soon  as  the  chain  is  released. 
Another  form  which  is  partially   automatic  is 
shown  in  Fig.  40.     When  the  chain  is  pulled 
it  raises   the    central  valve  from  its    seat  and 
allows  the  water  to  flow  down   the  flush  pipe 
until  the  tank  is  nearly  empty.     When  empty,  the  strong  suction 
seals  the  valve  which    remains    closed    until    the  chain  is  again 
pulled.      In  this  type  of  valve  a  single  pull  of  the  chain  is  sufii- 
cient  to  flusli  the  closet  without  further  attention. 

A  purely  automatic    flushing    device   is  shown  in  Fig.   41. 


Fig.  29. 


IS 


PLUMHINCJ. 


The  cluiiu  in  this  imsi'  is  attiu-hcd  to  tlic  liiii  of  tlu'  scat  so  tlial 
Avlioii  it  is  prosscd  ilowii,  tlu'  \alvo  in  (lie  cniiipartiiu'iit  at  tlic 
lH>ltonj,i'i)Mneotinij  with  the  tlush  pi[>e  iselosi'U  and  at  the  sanu;  time 


Fi-.  :50. 


FiK-  :il. 


¥\ir.  3^. 


Fig.  33. 


communication  i.s  opened  between  the  two  compartments.  When 
tlie  ]>ull  on  the  chain  i.s  rek^ased  the  valve  connecting  the  fliisli 
pipe  is  o[>ened  and  the  opening  between  tlie  compaittnents  closed 


PLUMBING. 


19 


Fir.  34. 


FiK.  35. 


20 


n.r.Mi;iN(;. 


so  thai  the  water  in  llu'  lower  portidii  of  the  tank  llows 
thnninh  llu'  llusli  piju'  into  t\\c  closet  aulomaticall}-,  and  wlien 
tMn|)ly  no  more  euii  lu'  ailniitted  until  llie  lever  is  again  pulled 
down  and  tlie  valve  in  the  partition  opened. 


V\''.   MS 


p-iu.  37. 


Faucets.  There  are  nian\-  different  foinis  of  faucets  iu' 
use.  The  most  coniuiou  is  the  ('ouij)ressiou  cock  shown  in  I'ie-. 
42.  This  has  a  removable  leather  or  asbestos  seat  wiiich 
requires  renewing  from  time  to  time  as  it  ])econies  wf)i'n. 
Fig.  43  shows  a  similai-  form,  in  whieh  tiie  valve  seat  is 
free  to  adjust  itself,  being  held  in   j)Iaee  by  a  spring.      Another 


Fig.  38. 


Fifr.  m. 


style  often  used  in  hotels  and  otiier  public  places  is  the  self-closing 
faucet.  These  are  fitted  with  springs  in  such  a  wa}-  tliat  they 
remain  closed  except  when  held  open.  Two  different  forms  are 
shown  in  Figs.  44  and  45. 

There  are  various  arrangements   for  mixing  the  hot  and  cold 
water  for  bowls  and  bath  ttdjs  before  it  is  discharj'ed.     This  is 


PLL'MBING. 


21 


:accompli,slied  by  liaving  botli  faucets  connect  with  a  common  nozzle. 
Such  a  device  for  a  lavatory  is  shown  in  Fig.  46. 


Fig.  .40. 


Fig.  41. 


Fig.  42. 


Fig.  4.S. 


SOIL  AND  WASTE  PIPES. 


Cast=Iron  Pipe.  There  are  many  different  forms  of  soil  pipes 
•and  littings,  and  one  can  best  acquaint  himself  with  these  by 
looking  over  the  catalogues  of  different  manufacturers.  Figs.  47 
'and  48  show  two  lengths  of  soil  pipe  ;  the  first  is  the  regular 
pattern,  liaving  only  one  hub,  and  the  second  is  a  length  of  double- 
hub  pipe  ;  this  can  be  used  to  good  advantage  where  many  short 
pieces  are  required. 

Figs.  49  to  57  show  some  of  the  principal  soil  pipe  fittings. 
Figs.  49,  50,  51,  52  and  53  show  quarter,  sixth,  ciglith,  sixteenth 


Ii2 


n.iMiiixc. 


aiul  rt'tuni  Ih'ikIs  ri'sp»'olivol\ ,  and  by  tlic  use  of  tlicsc  almost  any 
ili'siii'd  aiii^K'  i-an  he  ohtaiiied.  I  )itltM('iit  lines  of  pipe  nia\-  Ih) 
coimeeteil   by   means  of  the  Y  aiul   T-\    Wiaiiehcs  shown  in  Kit's. 


Fi},'.  44. 


Fi<r.  45. 


^^^ 


54,  o5,  of)  and  ,'u  .  The  T-Y  fitting,  Kig,  56,  is  used  in  plaee  of 
the  Y  hranch.  Fig.  54,  in  cases  wiieie  it  is  desiied  to  connect  two 
j^ipe.s  wliicii  run  perpendicuhir  to  each  otlier. 

The  double  T-Y,  Fig.  57,  is  conven- 
ient foi-  use  in  d(iui)le  houses  where  asingle 
soil  ]ii[)e  answers  for  two  lines  of  closets. 
Pipe  Joints.  Great  care  should  be 
given  to  making  uj)  the  joints  in  a  proper 
manner,  as  serious  i-esults  may  follow  any 
defe(;tive  w^orkmansliip  which  allows  sewer 
gas  to  escape  inlo  tlic  building.  In  mak- 
ing up  a  joint,  liist  jtlace  tin;  ends  of  the 
jtipes  in  position  and  fasten  them  rigidly, 
then  j)a(k  the  joint  with  the  best  [)icked 
oakum.  In  packing  the  oakum  around 
the  hub,  the  first  layer  must  be  twisted  into  a  small  rope  so  that 
it  will  drive  in  with  ea.se  and  still  not  pa.ss  thiough  to  the  inside 
of  the  pi^je  where  the  ends  join. 


FiR.  46. 


PLUMBING. 


23 


In  a  4-inch  pipe  the  packing  should  be  about  1  inch  in  thick- 
ness and  calked  perfectly  tight  so  that  it  will  hold  water  of  itself 
without  the  lead.      Just  before  the  packing  is  driven  tightly  into 


FiM-.  -47. 


Fig.  48. 


Fig.  49. 


Fig.  50. 


Fig.  51. 


Fig.  52. 


Fig.  53. 


Fig.  54. 


the  hub,  the  joint  should  be  examined  to  see  that  the  space  around 
the  hub  is  the  same,  so  that  the  lead  will  flow  evenly  and  be  of 
the  same  thickness  at  all  points,  as  the  expansion  and  contraction. 


24 


J'LlTiMIilNvi. 


will  w«>rk  iiit  iinpi'i  ItH't  ji>inl  loose  imu'li  sooiut  than  one  in  wiiich 
th.e  lead  is  of  an  v\cn  ihii-kiu'ss  all  the  way  aroumi.  Only  the 
lH?st  of  elean  soft  leatlshouUl  he  used  fortius  lanposc.  lu  calking 
in  llie  lead  after  it  has  heeii  poiwed,  j^Teat  eare  uuist  be  exercised, 
as  the  pipe,  if  «>f  standard  grade,  is  easily  crackeil  and  will  stand 
but  little  shoek  from  the  ealking  chisel  and  hanunei-. 

Fig.  .*)8  shows  a  section  through   the  calked  joint  of  a  cast 
iron  soil  pij)e. 


^r 


FiK.  5.-,. 


Fig.  57. 


Wrought  Iron  Pipe.  This  is  used  but  little  iu  counection 
with  the  waste  pipes  except  for  the  purpose  of  back  venting  where 
it  may  be  employed  with  screwed  joints  the  same  as  in  steam 
work.      It  is  sometimes  used  where  only  small  drain  pipes  are 


OAKUM 


Fig.  .58. 


necessary,  but  is  not  desirable  as  it   Ls  likely  to  liecome  choked 
with  mst  or  to  be  eaten  through  by  moisture  from  the  outside. 

Brass  Pipe.  Brass  pipe,  nickle  plated,  is  largely  used  for 
connecting  open  fixtures,  such  as  lavatories  or  bath  tubs,  with  the 
soil  pipe.  It  is  common  to  use  this  for  the  expo.sed  portions  of 
the  connections  and  to  use  lead  for  that  part  beneath  the  floor  or 
in  partitions.  The  various  fittings  are  also  made  of  biass  and 
finished  in  a  similar  manner. 


PLUMBING. 


25 


Lead  Pipe.  For  sinks,  batli  tubs,  laiindiy  tubs,  etc.,  noth- 
ing is  better  for  carrying  off  the  waste  water  than  lead  pipe,  for 
the  reason  that  it  has  a  smooth  interior  surface  which  offers  a 
small  resistance  to  the  flow  of  water,  and  does  not  easily  collect 
dirt  or  sediment.  It  can  also  be  bent  in  easy  curves  which  is  an 
advantage  over  fittings  which  make  abrupt  turns ;  this  is  especi- 
ally important  in  pipes  of  small  size. 

Pipe  Joints.  There  are  two  common  methods  of  making 
joints  in  lead  pijje,  known  as  the  "  cup  joint  "  and  the  "  wipe 
joint."  The  first  is  suitable  onl}'  on  small  pipes  or  very  light 
pressures.  This  is  made  by  flanging  tlie  end  of  one  of  the  pipes 
and  inserting  the  other,  then  filling  in  the  flange  with  solder  by 
means  of  a  soldering  iron,  see  Fig.  59.     In  making  this  joint  great 


SOLDER 


Fig.  59. 


Fig.  60. 


care  should  be  taken  that  the  ends  of  the  pipes  are  round  and  fit 
closely  so  there  will  be  no  chance  for  the  solder  to  run  through 
inside  the  pipe  and  form  obstructions  for  the  collection  of 
sediment. 

The  different  stages  of  a  wipe  joint  are  shown  in  Fig.  60. 
The  ends  of  the  pipes  are  first  cleaned  and  then  fitted  together 
as  shown  in  the  second  stage.  The  solder  is  melted  in  a  small 
cast  iron  crucible  and  is  carefully  poured  on  tlie  joint  or  thrown 
on  with^  a  small  stick  called  a  "spatting  stick."  As  the  solder 
cools  it  becomes  pasty  and  the  joint  can  be  worked  into  shape  by 
means  of  the  stick  or  a  soft  cloth,  or  both,  depending  upon  the 
kind  of  joint  and  stage  of  operation.  The  final  shape  and  smooth 
finish  is  given  with  the  cloth.  The  ability  to  nuike  a  joint  of  this 
kind  can  be  attained  only  by  practice,  and  printed  directions  are 


20 


ri.l   .MlUNli. 


of  litlle  value  as  loinpiiit'd  with  t)l»st'r\  alion  autl  artnal  jiractioe. 
This  is  the  stroiiLji'st  tiiul  ninsi  sulislai'tory  joint  that  can  be  made 
between  two  lead  pipes  oi-  a  lead  and  brass  or  eo|)per  pipe.  In 
the  iatti'r  t'ase  the  brass  or  eoppei-  shoiihi  be  eaifliilly  tiiunMl  as 
far  as  the  joint  is  to  extend  by  means  of  a  solderinsj^  irori. 

Wlieri'  leail  waste  pipes  are  to  b*-  connected  with  cast  iron 
soil  pipfs  a  brass  ferule  should  be  used.  Different  forms  of  these 
are  shown  in  FiiL,'s.  01  and  <'>'J.  The  lead  pipe  is  Mijx'd  to  the 
finished  eml  of  the  ferule  while  the  other  end  is  calked  into  the 
hub  of  the  cast  iron  i)ipe  in  the  manner  already  descrilx'd.  The 
ferule  should    be  made  heavy  so   as   not  t(J  be   injured  in  tiic  proc- 


\/SMED 


Fip.  fll. 


Fig.  62. 


ess    of    caikinsj;-.        Cup    joints     should     never     be     used    for    this 
puqiose. 

Tile  Pipes.  Nothing-  but  metal  piping  should  be  used  inside 
of  a  building,  but  in  solid  earth,  starting  from  a  point  about  10 
feet  away  from  the  cellar  wall,  we  may  use  salt-glazed,  vitrified,  or 
terra  cotta  pipe  for  making  the  connection  with  the  main  sewer. 
This  pipe  is  made  in  convenient  lengths  and  shapes  and  is  easily 
liandled.  Various  fittings  are  made  similar  in  foim  to  those 
already  described  for  cast  iron.  In  laying  tile  pipe  each  piece 
should  be  carefully  examined  to  see  that  ii  is  smooth,  round,  and 
free  from  cracks.  The  ends  should  fit  closely  all  around,  and  each 
length  of  pipe  should  fit  into  the  next  the  full  length  of  the  hub. 
In  making  the  joints  nothing  but  the  best  hydraulic  cement  should 
be  used,  and  great  care  should  be  taken  that  this  is  ])ressed  well 


PLUMBING. 


into  the  space  between  the  two  pipes.  All  cement  that  works 
through  into  the  interior  should  be  carefully  removed  by  means  of 
a  swab  or  brush  made  especially  for  this  purpose.  The  earth 
should  be  filled  in  around  a  pipe  of  this  kind  before  the  cement  is 
set  or  else  the  joints  are  likely  to  crack.  Fine  soil  should  be  filled 
in  around  the  pipe  to  a  depth  of  3  or  4  inches,  and  rammed  down 
solid,  and  the  ditch  may  then  be  filled  in  without  regard  to  the 
pipe.  No  tile  pipe  should  be  used  inside  of  a  house  or  nearer 
than  about  10  feet  for  the  reason  it  might  not  stand  the  pressure 
in  case  a  stoppage  should  occur  in  the  sewer.  This  kind  of  pipe 
is  not  intended  to  carry  a  pressure  and  when  used  in  this  way 
is  seldom  entirely  filled  with  watei'.  Joints  between  iron  and  tile 
piping  are  made  with  cement  in  the  manner  described  for  two 
sections  of  tile. 

Cesspools.  It  is  often  desired  to  install  a  system  of  plumb- 
ing in  a  building  in  the  country  or  in  a  village  where  there  is  no 
system  of  sewerage  with  which  to  connect.  In  this  case  it  becomes 
necessary  to  construct  a  cesspool.  This  is  always  undesirable,  but 
if  properly  constructed  and  placed  at  a  suitable  distance  from  the 
liouse  and  in  such  a  ])Osition  that  it  cannot  drain  into  a  well  or 
other  source  of  water  supply  it  ma}-  be  used  with  comparative 
safety.  Especial  care  should  be  taken  in  the  construction,  and 
when  in  use  it  should  be  regularly  cleaned.  One  form  of  cess- 
pool is  shown  in  Fig.  63.  This  consists  of  two  brick  chambers 
located  at  some  distance  from  the  building  and  in  a  position  where 
the  ground  slopes  away  from  it  if  possible.  The  larger  chamber 
has  a  clean-out  opening  in  the  top  which  should  be  provided  with 
an  air-tight  cover.  An  ordinary  cast  iron  cover  ma}-  be  made 
sufficiently  tight  by  covering  it  over  with  3  or  4  inches  of  earth 
packed  solidly  in  place.  A  vent  pipe  should  be  carried  from  the 
top  to  such  a  height  that  all  gases  will  be  discharged  at  an  eleva- 
tion sufficient  to  prevent  any  harm. 

The  smaller  chamber  is  connected  with  the  first  by  means  of 
a  soil  pipe  as  shown.  This  chamber  is  arranged  for  absorbing  the 
liquids  and  for  this  ])urpose.is  provided  with  lengths  of  j^orous 
tile  radiating  from  the  bottom  as  shown  in  the  plan.  The  house 
di-ain  connects  with  the  larger  chamber,  which  fills  to  the  level  of 
the   overfiow,  then  the  liquid  portion  of  the  sewage  drains  over 


28 


I'l.r.MKixc;. 


into  c'lijiinher  No.  "J  ami  is  aWsorhnd  throii^li  llif  pdious  lilc  hiaiulics. 
Tlio  solid  {Tart  rcmaiiis  in  cliauibcr  No.  Land  can  he  reinovcd 
fioiii  titui'  to  tiuu".  A  siiitahli'  trap  slioulil  of  course  be  placed 
in  the  honse  drain  in  the  same  mannci-  as  ihoiinh  connected  with 
u  street  sewei-.  'I'he  sjifetv  of  the  cesspool  will  depend  much  upon 
its  loi-ation,  its  <,aMieral  construetion  and  care  and  the  nature  of  the 
soil. 

TRAPS   AND  VENTS. 

Traps.       Tiie    best    method    of    connecting-    traps,   and    their 
actual  \ahu'  under  all  conditions,  are  matters  upon  whicli  there  is 


^  O  V -X)-'-';.N     CHAMBHH 
^~'  \\       NO  2. 

■--^■fi         I;  rz 

'V  /7  SO/L   PIP€. 


±!o 


C'' 


■^^--u^' 


1  i"*. 


^  ^  CHAMBER 
\  \  NO.I 

I  I  SOIL    P/PC 

/  /        raoM 
/  House 


1II=]' 


Fig.  63. 


much  difference  of  opinion.  Cities  also  vary  in  their  require- 
ments to  ii  greater  or  less  extent,  so  that  it  will  be  possible  to 
show  in  a  general  way  only  the  various  prineijjles  involved  and  to 
illustrate  what  is  considered  good  practice,  in  the  average  case,  at 
the  present  time. 

A  sepanite  trap  should  in  geneial  be  placed  in  the  wiuste  pipe 
from  each  fixture,  although  several  of  a  kind,  such  as  lavatories, 
etc.,  are  often  drained  through  a  common  trap,  as  shown  in  Fig.  r»4. 

In  addition  to  the  traps  at  the  fixtuies  a  main  or  running 
trap  i;,  placed  in  the  main  soil  pipje  outside  of  all  the  connections; 


PLUMBING. 


29 


this  is  sometimes  placed  in  a  manhole  just  outside  the  building, 
but  more  commonly  in  the  cellar  before  passing  through  the  wall ; 
the  foimer  method  is  much  to  be  preferred,  as  the  trap  may  be 
cleaned  without  admitting  gases  or  odors  to  the  house.  The  run- 
ning trap  has  been  shown  in  Fig.  29,  and  is  provided  with  a 
removable  cap  for  cleaning. 

The  agencies  which  tend  to  destroy  the  water  seal  of  traps 


Fio-.  (34.  . 

are  siphonage,  evaporation,  back  pressure,  capillaiy  action,  leakage 
and  accumulation  of  sediment. 

Siphonage.  This  can  best  be  illustrated  by  a  few  simple 
diagrams  showing  the  jn'inciples  involved.  In  Fig.  65  is  shown  a 
U  tube  with  legs  of  equal  length  and  filled  with  water.     If  we 


Fiy.  G5. 


Fi^-.  66. 


Fif;.  67. 


invert  the  tube,  as  shown  in  Fig.  66,  the  water  will  not  I'un  out, 
because  the  legs  are  of  equal  length,  and  contain  equal  weights 
of  water,  which  pull  downward  from  the  top  with  the  same  foi-(;e, 
tending  to  form  a  vacuum  at  the  point  A.  If  one  of  the  legs  is 
lengthened,  as  in  Fig.  67,  so  that  the  column  of  water  is  heavier  on 
one  side  than  on  the  other,  it  will  run  out,  while  atmospheric  pressure 
will  force  the  water  in  the  shorter  tube  up  over  the  bend,  as  there 


30 


i'i.r.Mi;iN(i. 


Fijr.  6S. 


woulil  Ih'  ho  pn-ssMn'  to  n-sist  lliis  ;ictioii  slioiild  t\\c.  coliiiim  of 
wattT  brrak  at  this  point.  This  action  is  also  assisted  l>v  tlie 
mlliosion  of  the  |)artich's  of  watii-  to  cai'h  other.  Tlie  colmiiii  of 
wjiliT  ill  the  tiiltf  may  hr  hkriu'd  to  a  \>\vvr  of  lh'xil)h'  i-opo 
hiiiiLriiij^  oviT  a  pulU'V  ;  wlieii  cMnial  h-ii^ths  haiii^  over  each  side  it 
will  remain  slalionaiy,  hut  if  drawn  over  one 
side  sliijfhtly,  so  tliat  one  end  is  heavier  than 
the  otiier,  the  whole  I'ope  will  he  drawn  over 
the  j)ulli'y  toward  the  longer  and  heavier 
end.  The  lirst  eause,  due  to  atmospheric 
pressure,  is  the  principal  reason  for  the  action 
of  siphons,  but  the  latter  assists  it  to  some 
extent.  If  the  shorter  leg  of  the  si[)hon  he 
di})peil  ill  a  vessel  of  water,  as  shown  in 
Fig.  68,  the  atmospheric  pressure,  which  he- 
fore  acted  on  the  bottom  of  the  water  in  the 
tube,  is  transferred  to  the  surface  of  tin; 
wat€r  in  the  vessel,  and  the  flow  through  the  tube  will  con- 
tinue until  the  water  level  in  the  vessel  falls  slightly  below  the 
end  of  the  tube  and  admits  air  pressure,  which  breaks  the  siphon 
action.  Fig.  »!9  shows  the  same  principle 
applied  to  the  trap  of  a  sink  or  ])owl. 
If  the  bowl  is  w'ell  tilled  with  water, 
so  that  when  the  plug  is  removed  from 
the  bottom,  the  waste  pipe  for  some 
di-stance  below  the  trap  is  tilled  with 
a  solid  column  of  water,  a  siphon  action 
will  be  set  up  like  the  one  just  de- 
scril>ed,  and  the  trap  will  ])e  diaincd. 
Frequently  a  sufhcient  amount  of  water 
runs  dow  n  from  the  fixture  and  sides  of 
the  pipe  above  the  trap  to  partially  re- 
.store  the  seal.  This  direct  action  of 
the  water  of  a  fixture  in  breaking  its  own  trap  si-al  by  siphoning 
is  called  "self-siphonage."' 

A  more  common  form,  where  two  or  more  fixtures  connect  with 
the  same  waste  pipe,  is  shown  in  Fig.  70.  In  this  case  the  seal 
of  the  lower  closet  is  broken  by  the  discharge  of  the  upper.    The 


Fijr.  CO. 


PLUMBING. 


31 


falling  column  of  water  leaves  behind  it  a  partial  vacuum  in  the 
soil  pipe,  and  the  outer  air  tends  to  rush  into  the  pipe  through 
the  way  of  least  resistance,  which  is  often  through  the  trap  seals 
of  the  fixtures  below.  The  friction  of  the  rough  sides  of  a  tall 
soil  pipe,  even  though  it  be  open  at  the  roof,  will  sometimes 
cause  more  resistance  to  air  flow  than  the  trap  seals  of  the  fixtures,, 
with  the  result  that  they  are  broken,  and 
gases  from  the  drain  are  free  to  enter  the 
building. 

Three  methods  have  been  employed  to 
prevent  the  destruction  of  the  seal  by  siphon- 
age.  The  first  method  devised  was  what  is 
known  as  "  back  venting,"  and  this  is  largely 
in  use  at  the  present  time,  although  careful 
experiments  have  shown  that  in  many  cases 
it  is  not  as  effective  as  it  was  at  first  sup- 
posed to  be,  and  is  considered  by  some 
authorities  to  be  a  useless  complication.  It 
is,  however,  called  for  in  the  plumbing  regu- 
lations of  many  cities,  and  will  be  taken  up 
briefly  in  connection  with  other  methods. 

Back  Venting.  This  consists  in  con- 
necting a  vent  pipe  at  or  near  the  highest 
part  of  the  trap,  as  shown  in  Fig.  71.  The 
action  of  this  arrangement  is  evident;  in 
place  of  the  waste  pipe  receiving  the  air 
necessary  to  fill  it,  through  the  basin,  after 
the  solid  column  of  water  has  passed  down, 
it  is  drawn  in  through  the  vent  pipe,  as 
shown  by  the  arrows,  and  the  seal  remains,  or  should  remain, 
unbroken.  It  also  prevents  "  self-siphonage "  by  breaking  the 
colunni  of  water  and  admitting  atmospheric  pressure  at  the 
highest  point  or  crown  of  the  trap.  The  vent  not  only  pre- 
vents the  seal  from  being  broken,  as  described,  but  allows  any 
gases  which  may  form  in  the  waste  pipe  to  escape  above  the ;oof 
of  the  house.  In  order  to  be  effective,  the  back  vent  should  be 
large,  but  even  when  of  the  same  size  as  the  waste  pipe,  the  flush- 
ing of  a  closet  will  oftentimes  break  the  seal,  especially  if  the 


Fig.  70. 


32 


I'M  .Mi;i.\(i. 


Vi'iit  {"ipt'  is  oi  coiisitK'rablr.  K'unth.  'l\\r  \fnt  oftt'ii  becomes 
chokiul,  either  wiili  the  jici-iumihitioii  of  seiliiiieiil  iiejir  the  Irap  or 
by  iiosl  or  siu»\\  at  tlie  to|»;  in  this  case  its  elYect  is  of  coiuse 
destroveil.  Another  tlisailvantaui-  ol"  the  hac-k  \v\\[  is  the  hasten- 
ing of  evaporation  froiii  tlie  trap  and  the  unseaUnL,'-  of  iixtures 
which  are  not  often  used. 

Tlie  second  method  of  guarding  against   the   h)ss  of  seal  hy 


Fi-.  71. 


FiK.  72. 


siphonage  is  to  make  the  body  of  the  trap  so  large  tliat  a  sufficient 
quantity  of  water  will  always  adhere  to  its  sides  after  siphoning 
to  restore  a  seal.  The  pot  or  ces.spool  tra{)  shown  in  Fig.  72  is 
based  on  this  ])i-inciple. 

The  third  method  consists  in  the  use  of  a  trap  of  such  form 
that  it  will  not  siphon,  and  will  at  the  same  time  be  self-cleaning. 
Among  othei"  types  the  centrifugal  trap,  shown  in  Figs.  34  and  35, 
is  claimed  to  fulfil  these  conditions.  The  pot  trap,  while  less 
affected  by  the  siphoning  action,  is  moie  or  less  objectionable  on 
account  of  i-etaining  much  of  the  sediment  and  solid  jiart  of  the 
sewage  whiih  falls  into  it. 

Local  Vents.  A  local  vent  is  a  l>ipe  connected  directly  with 
a  closet  or  urinal  for  carrying  off  any  odor  when  in  use.  It  has 
no  connection  with  the  soil  pipe,  unless  the  trap  seal  becomes 
broken,  and  is  not  provided  foi-  the  purpose  of  carrying  off  gases 
from  the  sewer.  A  urinal  ])rovided  with  a  local  vent  is  shown  in 
Fig.  73. 

Sometimes  a  small  i-egister  face  back  of  the  fixture,  and  con- 


PLUMBING. 


33 


necting  with  a  flue  in  the  wall,  is  used  in  place  of  the  regular 
local  vent.  In  order  for  a  vent  flue  of  either  form  to  be  of  any 
value,  it  nnist  be  warmed  to  insure  a  proper  circulation  of  air 
through  it.  This  is  done  in  some  cases  by  placing  a  gas-jet  at 
the  bottom  of  the  flue,  in  others  a  steam  or  hot  water  pipe  is 
run  through  a  portion  of  the  flue,  and  in  still  others  the  vent 
is  carried  up  beside  a  chimney  flue,  from  which  it  may  receive 
sufficient  warmth  to  assist  the  circulation  to  some  extent. 

Main  or  Soil  Pipe  Vent.  It 
is  customary  to  vent  the  main  soil 
pipe  by  carrying  it  through  the 
roof  of  the  building,  and  leaving 
the  end  open.  This  is  shown  in 
Pig.  74.  On  gravel  roofs  which 
drain  toward  the  center,  the  soil 
pipe  is  sometimes  stopped  on  a 
level  with  the  roof,  and  serves  as 
a  rain  leader.  In  other  cases  the 
roof  water  may  be  led  to  the  soil 
pipe  in  tlie  cellar.  If  the  latter 
method  is  used,  the  water  should 
pass  through  a  deep  trap  before 
connecting  with  the  drain.  These 
arrangements  tend  both  to  flush 
out  the  soil  pipe  and  trap  and 
prevent  the  accumulation  of  sedi- 
ment. 

Fresh  Air  Inlets.  The  fresh  air  inlet  shown  just  above  the  run- 
ning trap  Fig.  74  is  to  cause  a  circulation  of  air  through  the  soil 
pipe,  as  shown  by  the  arrows.  The  connection  should  be  made  just 
inside  of  the  trap,  so  that  the  entire  length  of  the  drain  Avill  be 
SAvept  by  the  current  of  fresh  air.  It  is  sometimes  advised  to 
extend  the  fresh  air  pipe  up  to  the  roof,  because  foul  air  may  at 
times  be  driven  out  by  heavy  flushing  of  the  drain  pipe,  but  where 
this  is  done  there  is  much  less  chance  for  circulation,  as  the  inlet 
and  outlet  are  nearly  on  a  level,  and  the  columns  of  air  in  them 
are  more  likely  to  be  balanced.  By  cai-ryiug  the  inlet  six  or  eight 
feet  above  the  ground  both  objections  are  overcome  to  some  extent, 


34 


Mi;iNG. 


unless  this  brinofs  it  noar  a  window,  wliii'h,  of  course,  would  not 
be  safe.  Tlu*  main  trap  does  not  r»'(|uirf  a  hack  vent,  for  sliould 
it  be  siphoned   umler  oidinary  eomlitioiis,  it  will  always  be  lilled 


Fig.  74. 


again  witliin  a  few  minutes;  and  if  the  main  soil  pipe  is  open  at 
the  top  and  all  fixture.?  are  propeily  tapped,  no  harm  would  come 
from  the  slight  leakage  of  gas  into  the  drain  under  these  condi- 


PLUMBING.  35 


tions,  and  some  engineers  recommend  tlie  omission  of  the  running 

trap. 

Where  a  house  drains  into  a  cesspool  instead  of  a  sewer,  it  is 
far  more  necessary  that  the  system  should  be  trapped  against  it 
as  it  gives  off  a  constant  stream  of  the  foulest  gases.  The  usual 
form  of  ru]ining  trap  serves  to  protect  the  house,  but  the  cesspool 
should  have  an  independent  vent  pipe  leading  to  some  unobjection- 
able point  and  carried  well  up  above  the  surface  of  the  ground. 

Disposal  of  Sewage.  In  cities  and  towns  having  a  system 
of  sewers,  or  where  there  is  a  large  stream  of  running  water  near 
by,  the  matter  is  a  simple  one.  In  the  first  case,  the  house  drain 
is  merely  extended  to  the  sewer,  into  which  it  should  discharge  at 
as  high  a  point  as  possible,  and  at  an  acute  angle  with  the  direction 
of  flow.  When  the  drain  connects  witli  a  stream  it  should  be 
carried  out  some  distance  from  the  shore  and  discharge  under 
watei-,  an  opening  for  ventilation  being  provided  at  the  bank. 
Where  there  are  neither  sewers  nor  streams,  the  cesspool  must  be 
used.  When  the  soil  is  sufficiently  porous  the  method  shown  in 
Fig.  63  may  be  employed.  Sometimes  the  sewage  is  collected  in 
a  closed  cistern  and  discharged  periodically  through  a  flush  tank 
into  a  series  of  small  tiles  laid  to  a  gentle  grade,  from  8  to  12 
inches  below  the  surface.  By  extending  these  tiles  over  a  sufficient 
area  and  allowing  from  40  to  70  feet  of  tile  for  each  person,  a 
complete  absorption  of  the  sewage  takes  place  by  the  action  of  the 
atmosphere  and  the  roots. 

PIPE  CONNECTIONS. 

The  Bath  Room.  There  are  different  methods  of  connect- 
ing up  the  fixtures  in  a  bath  room,  depending  upon  the 
general  arrangement,  type,  the  kind  of  trap  used,  etc.  Fig.  75 
shows  a  set  of  fixtures  coiniected  up  with  vented  traps.  Both  the 
soil  and  vent  pipes  are  carried  above  the  roof  with  open  ends. 
No  trap  or  fixture  should  be  vented  into  a  chimney,  as  is  quite 
conmionly  done  ;  this  may  work  satisfactorily  when  the  flues  are 
warm,  but  in  summer  time,  when  the  fires  are  out,  there  are  quite 
likely  to  be  down  drafts,  which  cause  the  gases  to  be  carried  into 
the  rooms  through  stoves  or  fireplaces.  The  vent  pipe,  although 
usually   carried    through   the    roof   independently,   is    sometimes 


:u; 


ri.iMi;iN(i. 


coniu'clod  with  the  soil  pipe  above  the  hitjliest  lixtuic  :  the  soil 
pijK»  is  often  made  a  larufer  si/.e  throiij^h  the  attic  space  and  above 
the  roof  in  (Htlci-  t(t  increase  the  upward  lh>w  of  air  tlirou<j;h  it. 
Kii^.  Tt>  .shows  a  set  of  bath  room  connections  in  which  iion-siphon- 
iiiiX  traps  are  used  without  l)ack  vt'ntin«j^ ;  this  is  a  simpler  and  less 
expensive  method  of  makinix  the  eoimections  and  is  especially 
i-eeonuucudcd  l)v  some  I'liixineers.  ItvS  efficiency  of  course  depends 
upon  llie  propi'r  workintr  of  the  traps. 


Tiie  l)ath  room  itself  should  l)e  well  lighted,  and  if  possible, 
in  a  location  where  it  will  receive  the  sun.  It  should  be  arranged 
so  that  it  mav  l^e  heated  to  a  higher  temperature  than  other  rooms 
in  the  house  if  desired,  and  it  should  also  be  thoroughly  ventilated, 
the  vent  register  being  placed  5  or  6  feet  above  the  floor  in  order 
that  it  may  carry  off  any  steam  which  rises  from  the  bath  tub. 
The  walls,  dooi-s,  etc.,  should  be  finished  in  a  way  to  make  them 
as  nearly  waterproof  as  possible  ;  some  form  of  good  enamel  i)aint 
amiwers  well  for  this  purpose.  Paper  should  never  be  nsed  on 
the  walls,  nor  carpets  on  the  floors,  which  should  be  of  hard  wood. 
Where  the  expense  is  not  a  matter  of  importance,  glazed  tile  may 
1)6  used  f«>r  the  floor  and  walls.      .Means  should  always  be  provided 


PLUMBING. 


37 


for  ventilating  the  bathroom  without  opening  the  door  into  the 

other  rooms,  and  the  greatest  care  should  be  taken  to  keep  not 

only  the  fixtures,  but  tlie  room  itself,  in  the  most  perfect  order. 

Urinal  Connections.     The  common  form  of  urinal  connection 


Fig.  76. 


is  shown  in  Fig.  14.  The  overflow  from  the  trap  ends  in  a  tee, 
the  lower  outlet  of  which  connects  with  tlie  soil  pipe  and  the 
upper  with  the  vent  pipe.  Where  several 
urinals  are  erected  side  by  side  it  is  usual  to 
omit  the  individual  traps,  using  the  direct 
outlet  connection  shown  in  Fig.  77.  Tliese 
connect  with  a  common  waste  pipe  and  drain 
through  a  single  trap  to  the  soil  pipe. 

Kitchen  Sink  Connections.  Fig.  78 
shows  the  usual  method  of  making  the  con- 
nections for  a  kitchen  sink.  The  waste  and 
vent  are  of  lead,  connected  with  the  main 
cast-iron  soil  and  vent  pipes  l)y  means  of 
brass  ferules  and  wiped  joints. 

5oil  and  Waste  Pipes.  Tlie  various  fixtures  have  been 
taken  up,  together  with  the  different  kinds  of  traps  wliicli  are  used 
in  connection  with  them,  and  also  the  general  methods  of  making 
the  various  connections  for  waste  and  vent.      We  will  next  take 


Fio-. 


rr.rMr.iNc. 


up  sonu*  i>f  lilt'  points  in  vi''j;ar(l  to  the  manner  ot  iinininn'  and 
supportin<^  tlir  (lilVncnt  pipes,  togotlin-  willi  the  proper  sizes  to  he 
useil  under  tlitVeient  eonditious. 

The  wasli'  pipes  of  necessity  eontain  nioie  ton!  matter  and 
therefore  more  harmful  gases  tlian  ilie  lixtnres.  so  that  especial 
eare  must  he  taken  in  their  arrangement  and  construction.  It  is 
advisahle  to  keep  all  J)iping  as  sinij)l(^  as  possihle,  using  as  few 
I'onnec-tions  as  is  consistent  with  the  proper  working  of  the 
system. 

The  lixtureson  each  tloor  should  he  arranged  to  comedirectly 
over  each  other,  so  as 
to  avoid  the  running  of 
lioi'izontal  pipes  across  or 
l)et\veen  the  floor  heams. 
The  sizes  of  pipes  com- 
monly used  require  such 
a  sharp  grade  that  llu'i'e 
is  not  sulHcieiit  space, 
in  ordinary  building  con- 
struction, hetween  the 
floor  hoards  aiul  ceiling 
lath  l»elow  for  horizontal 
runs  of  much  length. 
One  soil  pipe  is  usually 
sufficient  for  huildings 
of  ordinary  size,  and  in 
cold  climates  is  nee- 
essarily  carried  down  inside  the  huilding  to  prevent  freezing. 
One  or  more  waste  ])ipes  from  sinks,  hathtuhs,  etc.,  aie  usually 
recpiired  in  addition  to  the  soil  pipe  These  may  be  connected 
directly  with  the  soil  pipe  (thi'ough  traps),  if  located  near  it,  oi- 
may  1k'  cairied  to  the  basement  vertically  and  then  joined  with 
tlie  main  drain  j)ipe  inside  the  running  trap.  These  should  also 
l>e  place<l  on  the  inside  wall  of  the  house,  and,  if  necessary  to 
conceal  them,  the  boxing  used  should  be  put  together  in  such  a 
manner  that    it    may  he  easily  removed  for  inspection. 

Tlie  main   soil   \)\\k'  should  also  he  placed  where  it  can   be 


Fifr.    78. 


PLUMBING.  39 


seen,  so  that  leaks  may  be  easily  discovered;  it  is  commonly  run 
along  the  basement  wall  and  supported  by  suitable  brackets  or 
hangers.  If  carried  beneath  the  cellar  floor,  it  should  run  in  a 
brick  trench  with  removable  covers.  In  running  all  lines  of  pipe, 
Avhether  vertical  or  horizontal,  they  should  be  securely  supported 
and,  in  the  case  of  the  latter,  properly  graded.  Some  of  the 
various  kinds  of  hangers  and  supports  used  are  shown  in  Figs.  79 
and  80.  The  grade  of  the  pipes  should  be  as  sharp  and  as  uniform 
as  possible.  The  velocity  in  the  pipes  should  be  at  least  two  feet 
per  second  to  thoroughly  clean  them  and  prevent  clogging.  Gen- 
erally speaking,  the  pitch  of  the  jjipes  sliould  not  be  in  any  case 
-less  than  1  foot  in  50.     In  running  lines  of  soil  pipe,  it  is  best  to 


Fio-.  79.  Fig-.  80. 

set  the  joints  I'eady  for  calking  in  tlie  exact  positions  they  are 
to  occupy  and  resting  upon  the  supports  which  are  intended  to 
hold  them  permanently.  In  this  way  theie  is  less  liability  of  sag- 
ging or  loosening  of  the  joints  after  calking.  In  the  running  of 
vertical  pipes,  care  should  be  taken  to  have  them  as  straight  as 
possible  from  the  lowest  fixture  to    the  roof. 

It  is  very  necessary  that  the  pipes  be  given  such  an  align- 
ment that  the  water  entering  them  will  meet  with  no  serious 
obstructions.  Where  vertical  pipes  join  those  which  are  horizon- 
tal, they  should  be  given  a  bend  which  will  turn  the  stream  gradu- 
ally into  the  latter,  thus  preventing  any  resistance  and  the  result- 
ing accumulation  of  deposits.  Horizontal  pipes  may  be  joined 
with  vertical  pipes  without  a  bend,  as  the  discharge  will  be  suffi- 
ciently free  without  it.  However,  it  is  customary  to  use  a  Y  or 
T  branch,  giving  a  downward  direction  to  the  flow  when  connect- 
ing a  closet  or  other  fixture  where  tlieie  is  likely  to  be  much  solid 
matter  in  the  sewage.  Offsets  should  always  be  avoided  as  far 
as  possible,  as  they  obstruct  the  flow  of  both  water  and  air. 


40  rT.T^MIW\(;. 

PijH.'  f>i/es.  riic  must  iinpoitaiit  iciiuiicMU'iits  in  the  cas© 
of  ilischarcfe  jtipt'S  aic  that  they  (.-ai  rv  away  the  waste  matter  as 
tltoroiiLjlily  as  possible  without  stoppage  of  How  or  t'lUlyiiig,  and 
tliat  they  In*  well  ventilated.  In  order  to  accomplish  this  they 
must  l)e  given  such  sizes  as  experience  has  shown  to  be  the  best. 
When  water  having  solid  matter  in  suspension  half  fills  a  pipe,  the 
momentum  or  force  for  clearing  the  pipe  will  be  nnu-hgrt^atcr  than 
when  it  forms  oidy  a  shallow  stream  in  one  of  a  larger  size,  so  that 
in  proportioning  the  sizes  of  soil  pipes  and  diains  care  must  be 
taken    that    thev  are   not  made   larger  than    nccessarv,   for  if  the 


—  I 

Fig.  81. 

stream  becomes  too  shallow  the  pipes  will  not  be  properly  flushed 
and  deposits  are  likely  to  accumulate.  'I'he  amount  of  water  used 
in  a  hou.se  of  ordinary  size,  even  when  increased  by  the  roof  water 
from  a  heavy  rain,  will  easily  be  cared  for  by  a  4-incli  pipe  having 
a  good  pitcli.  While  a  pipe  of  this  size  would  seem  to  be  sufficient, 
it  is  found  by  experience  that  it  is  likely  to  become  clogged  at 
times  by  substances  which  through  carelessness  find  their  way  into 
the  drain,  so  that  it  seems  best  to  use  a  somewhat  larger  size. 
For  city  buildings  in  general,  it  is  recommended  that  the  main 
drain  should  not  be  less  than  5  or  6  inclies  in  diameter,  and  in 
ordinary  dwelling  houses  not  less  than  5  inches.  The  vertical 
soil  pijjes  need  not  be  larger  than  4  inches,  except  in  very  high 
buildings. 

\\'a.ste  pipes  may  vary  from  1]  inches  to  2  inches.  The 
wa.ste  from  a  single  bowl  or  lavatory  should  be  1]  inches  in 
diameter,  from  a  bathtub,  kitchen  sink  or  laundry  tub  1|  inches, 
from  a  slop  sink  1|  inches.  Smaller  pipes  should  never  be  used. 
In  laying  out  the  lines  of  piping,  provision  should  be  made  for 
clearing  the  pipes  in  case  of  stoppage.     Fig.  81  shows  how  this 


PLUMBING. 


41 


inay  be  done.  Clean-out  plugs  are  left  at  the  points  indicated  by 
tlie  arrows,  so  that  flexible  sticks  or  strips  of  steel  may  be  inserted 
to  dislodge  any  obstruction  which  may  occur. 

The  fresh-air  inlet  to  the  main  drain  pipe  has  already  been 
referred  to.  This  should  be  located  away  from  windows,  where 
foul  air  would  be  objectionable;  in  cities  they  may  be  placed 
at  the  curb  line  and  covered  with  a  grating.  Sometimes 
they  are  arranged  as  shown  in 
Fig.  82.  The  opening  is  made 
in  the  usual  way,  and  a  hood 
placed  over  the  inlet,  and  a  pipe 
leading  from  this  is  carried 
through  the  roof.  When  the 
circulation  of  air  is  upward 
through  tlie  main  soil  pipe  the 
opening  acts  in  the  usual  way, 
that  is,  as  a  fresh-air  inlet,  but 
should  there  be  a  reversal  of 
the  current  from  any  reason, 
which  would  discharge  foul  air 
from  the  sewer,  it  would  be 
caught     by     the      overbanging 

hood  and  carried  upward  through  the  connecting  vent  pipe  to  a 
point  above  the  roof.  A  general  layout  for  house  drainage  is 
shown  in  Fig.  83. 

PLUMBING  FOR  VARIOUS  BUILDINGS. 

Dwelling  Houses.  The  bathroom  fixtures,  laundry  tubs  and 
kitchen  sink,  with  the  possible  addition  of  a  slop  sink,  make  up  the 
usual  fixtures  to  be  provided  for  in  the  ordinary  dwelling  house. 
In  houses  of  larger  size  these  may  be  duplicated  to  some  extent, 
but  the  general  methods  of  connection  are  the  same  as  liave  already 
been  described  and  need  not  be  taken  up  again  in  detail. 

Apartment  Houses.  These  are  usually  made  up  of  duplicate 
flats,  one  above  the  other,  so  that  the  plumbing  fixtures  may  be  the 
same  for  each.  It  is  customary  to  place  the  bathrooms  in  the 
same  position  on  each  floor,  so  that  a  single  soil  pipe  will  care  for 
all. 


w/y/yy/Mm^'^' 


Fig.    82. 


42 


IM.rMIUNC. 


Hotels.  Ilt'ir,  as  in  tlu>  oase  just  ilescrihcd,  the  bathrooms 
are  phufd  nwv  altovf  anotlu'r,  so  that  a  siiiy^le  soil  pi[)e  may  care 
for  each  series,  an. I  the  prohU'in  tlieii  becomes  that  of  duplicat- 
ing the  hiyout  for  an  apartment  liouse.  In  addition  to  the 
j>rivate  Kiths  tliere  is  a  public  lavatory  or  toilet-room,  usually  on 
tlie  tii-st  tloor  or  in  the   basement.     Tliis  is  fitted  up  with  ehtsets^ 


Fig.  8.3. 


urinals  and  Ixjwls.  Tlie  closet  seats  and  urinals  are  placed  side 
by  side,  with  dividing  partitions,  and  connect  with  a  common  soil 
pipe  running  back  of  them  and  having  a  good  pitch.  Each  fixture 
should  have  its  own  trap.  The  flushing  of  the  fixtures  is  often 
made  automatic,  so  that  pressing  down  the  wooden  rim  of  a  closet 


PLUMBING. 


43 


seat  will  throw  a    lever  which  on  being  released  will  flush  the 

closet.     Urinals  are  commonly  made  to  flush  at  regular  intervals 

by  some  of  the  devices  already  shown.     The  lavatories  are  made 

up  in  long  rows,  as  shown 

in  Fig.  84. 

Railroad  Stations.  The 

plumbing    of    a     railroad 

station   is   similar  to  that 

of  a  hotel,  although  even 

greater    care    should     be 

taken  to  make  the  fixtures 

self-cleansing,      as      the 

patrons  are  likely  to  in- 
clude many  of  the  lowest 
and  most  ignorant  class  of 
people.  Special  attention 
should  be  given  to  both 
the  local  ventilation  of  the 
fixtures  and  the  general 
ventilation  of  the  room. 

Schoolhouses.  The 
same  general  rules  hold  in 
the  case  of  school  buildings 
as  in  hotels  and  railroad 
stations.  As  the  pupils 
are  under  the  direct  super- 
vision of  teachers  and  jani- 
tors it  is  not  necessary  to 
have-  the  fixtures  auto- 
matic to  as  great  an  extent 
a.s  in  the  cases  just  de- 
scribed, and  it  is  customary 
to  flush  the  closets  by 
means   of  tanks,  and  pull  &'^2 

chains  or  rods,  the  same  as  in  private  dwellings.     Tlie  urinals 
maybe  automatic  or  a  small  stream  of    water    maybe    allowed 
to  flow  through  them  continuously  during  school  hours 
form  for  this  class  of  work  is  shown  in  Fig.  85. 


A  good 


44 


PLU.Mr.lNci. 


Shops  and   Factories.     Some  siniplf    type  of   tixturc  which 
can  In*  tMsilx   (Mrt»(l  for  is  lu'st  in  l)nil(liii''s  {){'   this  kind. 


TESTING   AND  INSPECTION. 


All  pliunhiuf^  work  of  any  iiiijjoitaiice  shonhl  b(i  givoi   two 
teste;   the  fii-st,  called    the  " roughing  test,"  applies  only  to  the 


PLUMBING.  45 


soil,  waste  and  vent  pipes,  and  is  made  before  the  fixtures  are 
connected.  The  best  metliod  of  making  this  test  is  to  plug  the 
main  drain  pipe  just  outside  the  running  trap,  and  also  all  open- 
ings for  the  connections  of  fixtures,  etc.,  and  then  fill  the  entire 
system  with  water.  This  may  be  done  in  small  systems  through 
the  main  vent  pipe  on  the  roof,  and  in  larger  ones  by  making  a 
temporary  connection  with  the  water  main.  If  any  leaks  are 
present  they  are  easily  detected  in  this  way.  In  cold  weather, 
when  there  would  be  danger  of  freezing,  compressed  air  under  a 
pressure  of  at  least  ten  pounds  per  square  inch  may  be  used  in 
place  of  water.  Leaks  in  this  case  must  be  located  by  the  sound 
of  the  issuing  air.  The  water  test  is  to  be  preferred  in  all  cases, 
as  it  is  easier  to  make,  and  small  leaks  are  more  easily 
detected. 

The  final  test  is  made  after  the  fixtures  are  in  and  all  work 
is  completed.  There  are  two  ways  of  making  this  test,  one  known 
as  the  "peppermint  test,"  and  the  other  as  the  "smoke  test."  In 
making  either  of  these,  the  system  should  first  be  flushed  with 
water,  so  that  all  traps  may  be  sealed.  If  peppermint  is  used,  4 
to  6  ounces  of  oil  of  peppermint,  depending  upon  the  size  of  the 
system,  are  poured  down  the  main  vent  pipe,  and  then  a  quart  or 
two  of  hot  water  to  vaporize  the  oil.  The  vent  pipe  is  then 
closed,  and  tlie  inspector  must  carefully  follow  along  the  lines  of 
piping  and  locate  any  leaks  present  by. the  odor  of  the  escaping 
gas.  Another  and  better  way  is  to  close  the  vent  pipe  and 
vaporize  the  oil  in  the  receiver  of  a  small  air  pump,  and  then 
force  the  gas  into  the  system  under  a  slight  pressure.  The  re- 
ceiver is  provided  with  a  delicate  gage,  so  that  after  reaching  a 
certain  pressure  (which  must  not  be  great  enough  to  break  the 
trap  seals)  the  pump  may  be  stopped  and  the  pressure  noted.  If, 
after  a  short  time,  the  pressure  remains  the  same,  it  is  known  that 
the  system  is  tight ;  if,  however,  the  pressure  drops,  then  leaks 
are  present  and  must  be  located,  as  already  described.  Ether  is 
sometimes  used  in  place  of  peppermint  for  this  purpose. 

In  making  the  smoke  test  the  system  is  sealed,  and  the  vent 
pipes  closed  in  the  same  manner  as  for  tiie  test  just  described; 
smoke  from  oily  waste  or  some  similar  substance  is  then  forced 
into  the  pipes  by  means  of  a  bellows.     When  the  system  is  filled 


40  PLUMBING. 


with  suioko.  ;iih1  a  sliixliL  int'ssuro  pniduocd,  tlic  f:ut  is  sliowii  \)y 
a  lloai,  wliicli  rises  aiitl  iciiiaiiis  in  tliis  jxisition  it"  (lie  joints  are 
tight.  It"  tliere  are  le:iks,  the  float  falls  as  soon  as  the  l>ellr)\vs 
ait*  sl»)i)i»eil.  Leaks  may  he  detected  in  this  way,  hoth  hy  the 
odor  of  the  smoke  and  liy  the  issiiiiiL,^  jets  fioni  iealvs  of  imy  size. 
Special  maehines  are  made  for  hoth  the  peppermint  and  smoke  tests. 
'I'he  water  test  is  jjreferahle  for  ronnrjiino-  in,  and  the  smoke 
tost  for  the  final.  ICverv  system  of  plumlniig  should  be  tested  at 
leuiit  once  a  year. 

SEWERAGE  AND  SEWAGE  PURIFICATION. 

An  almndant  supply  of  pure  water  is  a  necessity  in  every  town 
and  city;  and  such  a  sup[)ly  having  been  secured  brings  up  the 
([iiestion  of  its  disposal  after  being  used.  This  is  plainly  the  re- 
vei-se  of  its  introduction.  As  it  was  distributed  through  a  net- 
work of  conduits,  diminishing  in  size,  with  its  numerous  bi-anches, 
so  it  may  1>e  collected  again  by  similar  conduits,  increasing  in  size, 
as  one  after  another  they  unite  in  a  common  outlet. 

This  fouled  water  is  called  sewage,  and  the  conduits  which  col- 
lect it  constitute  a  sewerage  system.  In  general,  sewage  is  dis- 
posed of  in  two  ways;  either  it  must  be  turned  into  a  bod}-  of 
water  so  huge  as  to  dilute  it  beyond  all  possibility  of  oiYence, 
and  where  it  cannot  endanger  human  life  by  }jolluting  a  public 
water-sujiply.  or  it  must  be  purified  in  some  manner. 

The  eoutluits  which  carry  water  collected  from  street  surfaces 
during  and  after  rains,  or  ground  water  collected  from  beneath 
the  surface,  are  called  drains.  When  one  set  of  conduits  lemoves 
.sewage  and  another  carries  surface  ami  ground  water,  it  is  said 
that  tlie  yf/Kirntr  system  of  sewerage  is  in  use.  Where  one  system 
<-onveys  l>oth  sewage  and  drainage  w^ater  it  is  called  th(i  <;oinhhie<i 
.HVHtem.  Various  modifications  of  these  two  systems  are  j)ossil)le, 
}K)th  for  "h'>1"  '!»;,.«  -Mid  foi-  limited  areas  within  the  same  town 
or  city. 

\  sanitary  sewerage  system  cannnt  be  installed  until  a  pul)lic 
w.'iter-sujtply  has  been  provirlefl.  It  is  needed  as  sof)n  as  that  is 
accomplished,  for  while  tlie  widls  can  then  be  abandoned  the  volume 
of  waste  water  is  greatly  increased  by  the  water-woiks  system.  Its 
foulness  is  also  much  increased  thiontrli  the  introduction  of  water- 


PLUMBING.  47 


closets.  Without  sewers  and  with  a  public  water-supply  cesspools 
must  be  used,  and  with  these  begins  a  continuous  pollution  of  the 
soil  much  more  serious  than  that  which  commonly  results  from 
closets  and  the  surface  disposal  of  slops. 

Among  the  data  which  should  first  be  obtained  in  laying  out 
a,  sewerage  system  are : 

First. — The  area  to  be  served,  with  its  topography  and  the 
general  character  of  the  soil. —  A  contour  map  of  the  whole  town 
or  city,  showing  the  location  of  the  various  streets,  streams,  ponds 
or  lakes,  and  contour  lines  for  each  5  feet  or  so  of  change  in  ele- 
vation, is  necessary  for  the  best  results.  The  general  character  of 
the  soil  can  usually  be  obtained  by  observation  and  inquiry  among 
residents  or  builders  who  have  dug  wells  or  cellars,  or  have  ob- 
served work  of  this  kind  which  was  being  done.  The  kind  of 
soil  is  important  as  affecting  the  cost  of  trenching  and  its  wetness 
or  dryness,  and  this,  together  with  a  determination  of  tlie  ground- 
water level,  will  be  useful  in  showing  the  extent  of  underdraining 
necessary. 

Second. — Wliether  the  separate  or  combined  system  of  sewer- 
age, or  a  compromise  between  the  two  is  to  be  adopted. —  These 
points  will  depend  almost  wholly  upon  local  conditions.  The  size 
and  cost  of  combined  sewers  is  much  greater  than  the  separate 
.system,  since  the  surface  drainage  in  times  of  heavy  rainfall  is 
many  times  as  great  as  the  flow  of  sanitary  sewage.  In  older 
towns  and  cities  it  sometimes  happens  that  drains  for  removing 
the  surface  winter  are  already  provided,  and  in  this  case  it  is  only 
necessary  to  put  in  the  sanitary  sewers  ;  or  again,  the  latter  may 
be  provided,  leaving  the  matter  of  surface  drainage  for  futui-e  con- 
sideration. 

If  the  sewage  must  be  purified,  the  combined  system  is  out 
of  the  (question,  for  the  expense  of  treating  the  full  flow  hi  times 
of  maximum  rainfall  would  be  enormous.  Sometimes  more  or  less 
limited  areas  of  a  town  may  require  the  combined  system,  while 
the  separate  system  is  best  adapted  to  the  remainder ;  and  again 
it  may  be  necessary  to  take  only  the  roof  water  into  the  sewers. 
As  already  stated,  local  conditions  and  relative  costs  are  the 
principal  factors  in  deciding  between  the  separate  and  combined 
systems. 


48  PllMIUXC. 

Third. —  Whether  subsoil  (Iraiimije  sh:ill  be  ])rovi(le(l. —  In 
most  eases  this  also  will  (Icpriid  u|i(iii  local  coiulitioiis.  It  is  al- 
wjiys  ail  Jidvant;jy;e  to  lower  tlic  i^roui id-water  IcncI  in  places 
where  it  is  siinicieiilly  high  tt>  make  the  i,n-ound  wet,  at  or  near  the 
surfaee  during  a  large  part  of  the  year.  In  addition  to  renderino- 
the  soil  dry  around  and  beneath  cellars,  the  la\ing  of  underdrains 
is  of  sui'h  aid  in  sewer  eonstruetion  as  to  warrant  their  introduc- 
tion for  this  purpose  alone.  This  is  the  case  where  tlie  trenches 
are  so  wet  as  to  render  the  making  and  setting  of  cement  joints 
ditheult.  The  aim  in  all  good  sewer  work  is  to  reduce  the  infil- 
tration of  ground  water  into  the  pipes  to  the  smallest  amount; 
but  in  very  wet  soil,  tight  joints  can  be  made  only  with  difficulty, 
and  never  with  absolute  certainty.  Cases  have  been  known  where 
fully  one-half  the  total  volume  of  sewage  discharged  consisted  of 
ground  water  which  had  worked  in  through  the  joints. 

Fourth. —  The  best  means  for  the  final  disposal  of  the 
sewage. —  Until  recently  it  was  turned  into  the  nearest  river  or 
lake  where  it  could  be  discharged  with  the  least  expense.  The 
principal  point  to  be  observed  in  the  disposal  of  sewage  is  that 
no  public  water-supply  shall  be  endangered.  At  the  present  time 
no  definite  knowledge  is  at  hand  regarding  the  exact  length  of 
time  that  disease  gerriis  from  the  human  system  will  live  in  water. 
The  Massacluisetts  legislature  at  one  time  said  that  no  sewer 
should  discharge  into  a  stream  within  20  miles  of  any  point  where 
it  is  used  for  public  water-supply,  but  it  is  now  left  largely  in  the 
hands  of  the  State  Board  of  Health.  There  may  be  cases  where 
sewage  disposal  seems  to  claim  jn-eference  to  water  sup[)ly  in  the 
use  of  a  stream,  but  each  case  must  be  decided  on  its  own  merits. 
Knowing  the  amount  of  water  and  the  probable  quantity  and 
character  of  the  sewage,  it  is  generally  easy  to  determine  whether 
all  of  the  crude  sewage  of  a  city  can  safely  be  discharged  into  the 
bo«ly  of  water  in  question.  Averages  in  this  case  should  never 
be  used;  the  water  available  during  a  hot  and  diy  summer,  when 
the  stream  or  lake  is  at  its  lowest,  and  the  banks  and  beds  are  ex- 
posed to  the  sun,  is  what  must  be  considered.  Where  sewage  is 
discharged  into  large  bodies  of  water,  either  lakes  or  the  ocean,  it 
is  generally  necessary  to  make  a  careful  study  of  the  prevailing 
currents  in  order  to  determine  tlie  most  available  point  of  discharge, 


PLUMBING.  49 


in  order  to  prevent  the  sewage  becoming  stagnant  in  bays,  or  the 
washing  ashore  of  the  lighter  portions.  Such  studies  are  com- 
monly made  with  floats,  which  indicate  the  direction  of  the  exist- 
ing currents. 

Fifth. —  Population,  water  consumption  and  volume  of  sewage 
for  which  provision  should  be  made,  together  with  the  rainfall 
data,  if  surface  drainage  is  to  be  installed. — The  basis  for  population 
studies  is  best  taken  from  the  census  reports,  extending  back  many 
years.  By  means  of  these  the  probable  growth  may  be  estimated 
for  a  period  of  from  30  to  50  years.  In  small  and  rapidly  grow- 
ing towns  it  must  be  remembered  that  the  rate  of  increase  is  gen- 
erally less  as  the  population  becomes  greater. 

It  is  desirable  to  design  a  sewerage  system  large  enough  to 
serve  for  a  number  of  years,  20  or  30  perhaps,  altliough  some 
parts  of  the  work,  such  as  pumping  or  purification  works,  may 
be  made  smaller  and  increased  in  size  as  needed. 

The  pipe  system  should  be  large  enough  at  the  start  to  serve 
each  street  and  district  for  a  long  period,  as  the  advantages  to  be 
derived  from  the  use  of  city  sewers  are  so  great  that  all  houses 
are  almost  certain  to  be  connected  with  them  sooner  or  later.  It 
is  often  necessary  to  divide  a  city  into  districts  in  making  esti- 
mates of  the  probable  growth  in  population.  Thus  the  residential 
sections  occuj^ied  by  the  wealthiest  classes  will  be  comprised  of  a 
comparatively  small  jjopulation  per  acre,  due  to  the  large  size  of 
the  lots.  The  population  will  grow  more  dense  in  the  sections 
occupied  by  the  less  wealthy,  the  well-to-do  and  finally  the  tene- 
ment sections.  In  manufacturing  districts  the  amount  of  sewage 
will  vary  somewhat,  depending  upon  the  lines  of  industry- 
carried  on. 

The  total  water  consumption  dejjends  mainly  upon  the  popu- 
lation, but  no  fixed  rule  can  be  laid  down  for  determining  it 
beforehand.  It  is  never  safe  to  allow  less  than  60  gallons  per 
day  per  capita  as  the  average  water  consumption  of  a  town  if 
most  of  the  people  patronize  the  public  water-supply.  In  general 
it  is  safer  to  allow  100  gallons.  The  total  daily  flow  of  sewage  is 
not  evenly  distributed  through  the  24  hours.  The  actual  amount 
varies  widely  during  different  hours  of  the  day.  In  most  towns 
there  should  be  little  if  any  sewage,  if  the  pipes  are  tight  enough 


oO  PLITMBING.  , 


lo  |tr«'\oin  inwaid  li':ik;i^<',  luMWfcii  almiit  10  n'l-lock  in  the 
I'voninij  and  I  in  ilio  niorninL;.  I'loin  [-j  to  '■'■  o(  the  daih  How 
usually  oorui-s  in  from  1>  to  1:^  hours,  tlic  particular  hours  varyin<,»- 
in  diilVrent  conunuuilics.  This  is  not  of  ini[)ortan('('  in  dcsignintf 
till'  l»il'»'  sysltMii.  hut  only  alVrcts  the  dis{)t)sal. 

Rainfall  data  is  usually  hard  to  ohtaiu  cxc-ept  in  the  cities 
and  lari;tM-  towns.  in  rases  of  this  kind  the  data  of  niMii^hhoi-iiif 
town  or  cities  may  he  used  if  availahlc.  Monthly  or  weekly 
totals  are  of  little  \aliie.  as  it  is  necessary  to  pi-ovide  for  the 
heaviest  rains,  as  a  severe  shower  of  15  minutes  may  cause  more 
inconvenience  and  damage,  if  the  sewers  are  not  sufficiently  large, 
than  a  steady  rain  extending  over  a  day  or  two.  A  maximum 
mte  of  1-ineli  ])er  hour  will  usuall}'  cover  all  ordinary  conditions. 
The  proportion  which  will  reach  the  sewers  during  a  given  time; 
will  depend  upon  local  conditions,  such  as  the  slope  of  land, 
Avliether  its  surface  is  covered  with  houses  and  i)nved  streets, 
cultivated  fields  or  forests,  etc. 

iSi.rf/i. —  Extent  and  cost  of  the  proposed  system. —  This  is  a 
matter  largely  dependent  upon  the  local  treasury,  or  the  Avilling- 
ness  of  the  people  to  i>ay  general  taxes  or  a  si)ecial  assessment 
for  the  l.)enefits  to  he  derived. 

DESIGN  AND  CONSTRUCTrON. 

'i"he  first  stej)  is  to  lay  out  the  i)ipe  or  conduit  system.  For 
this  the  topographical  map  already  mentioned  will  he  found 
useful.  This,  however,  should  he  supplemented  hy  a  profile  of  all 
the  streets  in  which  sewers  are  to  he  laid,  in  order  to  determine 
the  proper  grades.  In  laying  out  the  pipe  lines,  special  diagrams 
and  taljles  which  have  heen  jjrepaied  for  this  purpose  may  he 
used.  In  the  separate  system  it  i^  generally  hest  to  use  8"  pipe 
as  the  smallest  size  to  lessen  the  risk  of  stoijoao-e,  although  (!" 
pipe  is  ample  for  the  volume  of  sanitary  sewage  from  an  ordinary 
residence  street  of  medium  length.  Pipe  seweis  are  generally 
made  of  vitrified  clay,  with  a  salt-glazed  surface.  Cement  pipe  is 
also  used  in  some  cities.  The  size  of  pipe  sewers  is  limited  to 
30  inches  in  diameter,  owing  to  the  difficulty  and  exi)ense  of 
making  the  larger  pipe  and  the  comparative  ease  of  laying  hrick 
sewers  of  any  size  fir»m  24  or  .".0  inches  up.      In  very  wet  ground, 


PLUMBING.  51 


cast  iron  pipe  with  lead  joints  is  used,  either  to  prevent  inward 
leakage  oi-  settling  of  the  pipe. 

The  pipes  should  be  laid  to  grade  with  gieat  care  and  a  good 
alignment  should  be  secured.  Holes  should  be  dug  for  the  bells 
of  tlie  pipe,  so  that  they  will  have  solid  bearings  their  entire 
lengtli.  If  rock  is  encountered  in  trencliing,  it  mil  be  necessary 
to  provide  a  bed  for  the  pipe  whicli  will  not  be  washed  into  fis- 
sures by  the  stream  of  subsoil  water  whicli  is  likely  to  follow  the 
sewer  when  the  ground  is  saturated, 

Underdrains.  Where  sewers  are  in  wet  sand  or  gravel, 
underdrains  may  be  laid  beneath  or  alongside  tlie  sewer.  These 
are  usually  tlie  ordinary  agricultural  tiles,  from  3  inches  in 
diameter  upward.  They  have  no  joints,  being  simply  hollow 
cylinders,  and  are  laid  with  their  ends  a  fraction  of  an  inch 
apart,  wrapped  with  a  cheap  muslin  cloth  to  keep  out  the  dirt 
until  the  matter  in  tlie  trench  becomes  thoroughly  packed  about 
them.  Tiiese  drains  may  empty  into  the  nearest  stream,  provided 
it  is  not  used  for  a  public  water-supply. 

rianholes.  These  should  be  placed  at  all  changes  of  grade 
and  at  all  junctions  between  streets.  They  are  built  of  brick  and 
afford  access  to  the  sewer  for  inspection ;  in  addition  to  this  they 
are  sometimes  used  for  flushing.  They  are  provided  with  iron 
covers  wliieh  are  often  pierced  with  holes  for  ventilation. 

Sewer  Grades.  The  grades  of  sewers  should  be  sufficient 
where  possible,  to  give  them  a  self-clearing  velocity.  Practical 
experiments  show  tliat  sewers  of  the  usual  sections  will  i-emain 
clear  with  the  following  minimum  grades :  Separate  house  con- 
nections, 2  per  cent;  (2-feet  fall  in  each  100  feet  of  length) 
small  street  sewers,  1  per  cent ;  main  sewers,  0.7  per  cent.  These 
grades  may  ])e  reduced  slightl}-  for  sewers  cariying  only  rain  or 
quite  pure  water. 

'i'he  following  formula  may  be  used  for  computing  the  mini- 
mum grade  for  a  sewer  of  clear  diameter  equal  to  "(7"  inches 
and  either  circular  or  oval  in  section. 

Miiiinium  grade,  in  per  cent  = 


5  a  +  ')  0 
Flushing  Devices.     Where  very  low  grades  are  unavoidable 


oii  ri.rMr.i\(;. 

ami  at    llu'   head   of   luaiich   sewers,  \\  Ihtc    ilic    volume   c»f   llow  is 
small.  tliisliiiiLT  UKiv  I'c  nsed  with  adx  aiitat^t'. 

In  soini'  ca.s»*s  water  is  turned  into  tlu^  sewer  thronti^h  a  man- 
lu>le,  from  somi'  jxmd  or  stream,  oi-  fiom  the  pnhlie  water-works 
system.  (lenerally,  liowevei-,  the  watei-  is  allowed  to  aecunmlate 
In'foiv  heinor  iliseluirjjjed,  l)y  elosin^^  up  the  lower  side  of  the  man- 
hole tmtil  the  water  ])artially  lills  it,  thcMi  suddenly  reknisin<(  it 
and  allowiny^  the  water  to  lush  thronuh  th(^  j)i[)e.  Instead  of 
usiiifj  i-K'ar  water  from  outside  for  this  |)urpose,  it  may  l)e  siifiicient 
at  some  points  on  the  system  to  sim[>ly  hack  up  the  sewage,  hy 
ch-tsin«r  the  manhole  outlet,  thus  tlushiiujf  the  sewer  with  tlie  sewaL'e 
itself.  Where  frequtMit  and  reguhir  Hushing  is  required,  automatic 
devices  are  often  used.  These  usually  operate  by  means  of  a  self- 
discharging  siphon,  although  there  aie  other  devices  operated  by 
means  of  the  weight  of  a  tank  which  iills  and  empties  itself  at 
regular  intervals. 

House  Connections.  Provision  for  house  connections  should 
be  made  when  the  sewers  are  laid,  in  order  to  avoid  breaking  up 
the  streets  after  the  sewers  are  in  use.  Y  branches  should  be  put 
in  at  frequent  intervals,  say  from  25  feet  apart  upAvards,  according 
to  the  character  of  the  street.  When  the  sewer  main  is  deep 
down,  quarter  bends  are  sometimes  provided,  and  the  house  con- 
nection [)ij)e  carried  vertically  upwards  to  within  a  few  feet  of  the 
surface  to  avoid  deep  digging  when  connections  are  made.  Wheie 
house  connections  are  made  with  the  main,  or  w  here  two  sewers 
join,  the  direction  of  flow  shoidd  be  as  nearly  in  the  same  direc- 
tion as  possible,  and  the  entering  sewer  should  be  at  a  little  higher 
level  in  order  to  increase  the  velocity  of  the  inflowing  sewage. 

Depth  of  Sewers  Below  the  Surface.  No  geneial  rule  can 
be  followed  in  this  matter  except  to  place  them  low  enough  to 
secure  a  proper  g^rade  for  the  house  connections,  which  are  to  be 
made  with  them.  They  must  be  kej)t  below  a  j)oint  where  there 
would  ])e  trouble  from  freezing,  but  the  natural  depth  is  usually 
sufficient  to  prevent  this  in  most  cases. 

Ventilation  of  Sewers.  There  is  more  or  less  difference  in 
opinion  in  regard  to  the  proper  method  of  ventilating  sewer  mains. 
Ventilation  through  house  soil  pipes  is  generally  approved  where 
the  sewers  and  house  connections  are  properly   constructed   and 


PLUMBING.  53 


•operated,  and  where  the  houses  on  a  given  street  are  of  a  uniform 
height,  so  that  the  tops  of  all  the  soil  pipes  will  be  above  the  high- 
est windows.  Where  the  houses  are  uneven  in  height,  or  where 
the  sewerage  system  or  connections  are  not  well  designed  or  con- 
structed, it  is  recommended  that  main  traps  should  be  placed  on 
all  soil  pipes,  and  that  air  inlets  and  air  outlets  be  placed  on  the 
sewers  at  intervals  of  from  300  to  400  feet. 

The  Combined  System.  The  principal  differences  between 
this  and  the  separate  system  are  in  the  greater  size  of  conduits 
and  the  use  of  catch-basins  or  inlets  for  the  admission  of  surface 
water.  They  are  generally  of  brick,  stone  or  concrete,  or  a 
combination  of  these  materials,  instead  of  vitrified  pipe. 

Another  difference  is  the  provision  for  storm  overflows,  by 
means  of  which  the  main  sewers  when  overcharged  in  times  of 
heavy  rainfall  may  empty  a  part  of  their  contents  into  a  nearby 
stream.  At  such  times  the  sewage  is  diluted  by  the  rain-water, 
while  the  stream  which  receives  the  overflow  is  also  of  unusually 
large  size. 

Size,  5hape  and  Material.  The  actual  size  of  the  sewer, 
and  also  to  a  large  extent  its  shape  and  the  material  of  which  it  is 
constructed,  depends  upon  local  conditions.  Where  the  depth  of 
flow  varies  greatly  it  is  desirable  to  give  the  sewer  a  cross-section 
•designed  to  suit  all  flows  as  fully  as  possible. 

The  best  form  to  meet  these  requirements  is  that  of  an  egg 
with  its  smaller  end  placed  downward.  With  this  form  the 
greatest  depth  and  velocity  of  flow  is  secured  for  the  smallest 
amount  of  sewage,  thus  reducing  the  tendency  to  deposits  and  stop- 
pages. Where  sewers  have  a  flow  more  nearly  constant  and  equal 
to  their  full  capacity  the  form  may  be  changed  more  nearly  to  that 
of  an  ellipse.  For  the  larger  sewers  brick  is  the  most  commou 
material,  both  because  of  its  low  cost  and  the  ease  with  which  any 
form  of  conduit  is  constructed.  Stone  is  sometimes  used  on  steep 
grades,  especially  where  there  is  much  sand  in  suspension,  which 
would  tend  to  wear  away  the  brick  walls.  Concrete  is  used  where 
leakage  may  be  expected  or  where  the  material  is  liable  to  movement, 
l)ut  is  more  connnonly  used  as  a  foundation  for  brick  construction. 
A  catch-basin  is  generally  placed  at  each  street  corner  and 
provided  with  a  grated  opening  for  giving  the  surface  water  access 


54  iM.iMr.ixt;. 

to  ;i  iIkiiiiIht  or  Inisiii  liciuMth  tlic  sidt'walk,  from  wliicli  ;i  pipe 
le;uls  to  llic  si'WtT.  ( ';it(li-l);isiiis  niiiy  he  luovidcd  with  walcr 
tr.ijis  to  jiii'Vriit  tln'  sfwci-  ;iir  iVoiii  iciicliiiiL;-  the  sheet,  Idit  traps 
are  inieortain  in  tlieii-  aelimi.  as  llie\  are  likelv  [n  lieeoine  unsealed 
throiii^li  cvaporat  inn  in  diy  w callici'.  I'o  prexent  I  lie  earr\  in^'  of 
sand  and  diil  into  the  sewers.  eat(di-ltasins  should  he  proNided 
witli  silt  «'hanil)eis  o(  considerahle  depth,  with  oNcrllow  pipes 
h>adin<^  to  tin*  st'wer.  'V\\v  lu'avy  matter  which  falls  to  the 
IxUttMiis  of  tlies(>  ehandiers  may  be  icmoved  hy  Imckcts  and  called 
away  at  proper   intervals. 

5torm  Overflows.  The  main  ])oint  to  he  considci'cd  in  the 
ronstrnetion  of  stoini  overflows  is  to  ensure  a  diseharge  into 
another  conduit  w  hen  the  A\ater  reaches  a  certain  elevation  in  the 
main  sewer.  'I'liis  may  Ite  carried  out  in  different  ways,  dejx'nding 
upon  the  a\ailahh'  j)()inls  for  overflow. 

Pumping  Stations.  TJie  greater  })art  of  the  sewerage 
systems  in  the  I'niied  States  operate  w^holly  hy  gi'avity.  hut  in 
some  eases  it  is  necessary  to  ]»umi)  a  part  or  the  Avliole  of  the 
sewage  of  a  eity  to  a  higher  level.  The  lifts  required  are  usually 
low,  so  that  high-priced  maeliinery  is  not  required.  In  general 
the  sewage  sliouhl  he  screened  hefore  it  reaches  tlu;  pumjis. 

Where  [)um[)ing  is  necessary,  receiving  or  storage  chambers 
are  sometimes  used  to  e<puili/.e  the  work  required  of  the  pumps, 
thus  making  it  jxissihle  to  shut  down  tlui  [)lant  at  night.  Such 
reservoii-s  shonld  he  covered,  unless  in  very  isolated  localities. 
The  force  main  or  discharge  pipe  from  the  pumps  is  usually  short, 
and  is  generally  of  cast  iron  put  together  in  a  mainu'i'  similai-  to- 
that  used  for  water-sui)ply  systems. 

Tidal  Chambers.  Wherci  sewage  is  dischaiged  into  tide 
water  it  is  often  nec«'ssary  to  })if)vide  storage  oi'  tidal  chambers,  so 
that  the  sewage  may  bt;  discdiarged  only  at  ebb  tides.  'IMiese  are 
constructed  similar  to  other  reservoirs,  except  that  they  must 
have  ample  discharge  gates,  so  that  they  may  Ixi  emptied  in  a 
short  time.  Tliey  are  sometimes  made  to  work  automatically  l)y 
tlie  action  of  the  tide. 

SEWAGE  PURIFICATION. 

Before  taking  up  this  subject  in  detail  it  is  well  to  cotisider 
what  sewage  is,  from  a  chemical  standpoint. 


PLUMBING.  55 


When  fresh,  it  appears  at  the  mouth  of  an  outlet  sewer 
as  a  milky-looking  liquid  with  some  large  particles  of  matter 
in  suspension,  such  as  orange  peels,  rags,  paper  and  various 
other  articles  not  easily  broken  up.  It  often  has  a  faint, 
musty  odor  and  in  general  appearance  is  similar  to  the  suds-water 
from  a  family  laundry.  Nearly  all  of  the  sewage  is  simply  water, 
the  total  amount  of  solid  matter  not  being  more  than  2  parts  in 
1,000,  of  which  half  may  be  organic  matter.  It  is  this  1  part  in 
1,000  which  should  be  removed,  or  so  changed  in  character  as  to 
render  it  harmless. 

The  two  systems  of  purification  in  most  common  use  are 
"  chemical  precipitation  "  and  the  "  land  treatment."  Mechanical 
straining,  sedimentation  and  chemical  precipitation  are  largely 
removal  processes,  while  land  treatment  by  the  slow  process  of 
infiltration,  or  irrigation,  changes  the  decaying  organic  marter  into- 
stable  mineral  compounds. 

Sedimentation.  This  is  effected  by  allowing  the  suspended 
matter  to  settle  in  tanks.  The  partially  clarified  liquid  is  then' 
drawn  off  leaving  the  solid  matter,  called  "  sludeg,"  at  the  bottom 
for  later  disposal.  This  system  requires  a  good  deal  of  time  and 
large  settling  tanks ;  therefore  it  is  suital)le  only  for  small  quanti- 
ties of  sewage. 

Mechanical  Straining.  This  is  accomplished  in  different 
ways  with  varying  degrees  of  success.  Wire  screens  or  filters  of 
various  materials  may  be  employed.  Straining  of  itself  is  of  little 
value  except  as  a  step  to  further  purification,  Beds  of  coke  from 
6  to  8  inclies  in  depth  are  often  used  with  good  results. 

Chemical  Precipitation.  Sedimentation  alone  removes  only 
such  suspended  matter  as  will  sink  by  its  own  weight  during  the 
comparatively  short  time  wliich  can  be  allowed  for  the  process. 

By  adding  certain  substances  chemical  action  is  set  up,  which 
greatly  increases  the  rapidi^ty  with  which  precipitation  takes  place. 

Some  of  the  organic  substances  are  brought  together  by  the 
formation  of  new  compounds,  and  as  they  fall  in  flaky  masses- 
they  carry  with  them  other  suspended  matter. 

A  great  number  and  variety  of  chemicals  have  been  employed 
for  this  purpose,  but  tliose  wliich  experience  has  shown  to  be  most 
useful  are  lime,  sulphate  of  alumina  and  some  of  the  salts  of  iron. 


00  PLl'MHING. 


The  Ih'sI  cluMiiiial  to  use  in  :iiiy  ^ivcii  (msc  dcju'iids  ui)<)ll  tlio 
clianu'ttT  of  the  scwai^r  and  tlic  rrlaliNC  cost  in  liiat  lot-alitv. 
Linif  is  tliiMp,  l>iil  tlu>  larn'c  ([uantity  rt'(|uiit'(l  Lj'i'c'atly  in- 
cn-asi's  tlu'  amount  ot  sliulut'.  Sulphate  ol  aluuiiiia  is  iiioih^ 
oxpt'iisivt",  hill  is  olti'ii  used  to  advantage  in  connection  with 
lime.  Where  an  acid  se\\aL;e  is  to  he  treated,  Hme  ah»ne  should  l)e 
us.-d. 

Tlie  eliemiiaLs  shouUl  hi'  added  to  the  sewao^c  and  thornng'ldy 
niived  l>efore  it  reaches  the  settlinuc  tank  ;  this  may  \)C  eil'ected  l)v 
tlie  use  of  projeetions  or  IjaflliiiL;"  phitcs  phicccl  in  tiie  conihii'. 
leading  to  the  tank.  The  hest  results  are  ohtained  hy  means  oi" 
long,  narrow  tanks,  and  they  should  he  operated  on  the  continiuAis 
rather  than  the  intermittent  plan.  The  width  of  the  tank  should 
be  about  one-fourtli  its  length.  In  the  continuous  method  the 
sewage  is  constantly  flowing  into  one  part  of  the  tank  and  dis- 
charging from  another.  In  the  intermittent  system  a  tank  is  tilled 
and  then  the  flow  is  turned  into  another,  allomng  the  sewage  in 
the  lirst  tank  lo  come  to  rest.  In  the  continuous  })lan  the  sewage; 
generally  flows  through  a  set  of  tanks  without  hiterrupticm  until 
one  of  the  compartments  needs  cleaning.  The  clear  portion  is 
drawn  off  from  the  top,  the  sludge  is  tlien  removed,  and  the  tank 
thoroughly  disinfected  before  being  put  in  use  again.  The  satis- 
factory disposal  of  the  sludge  is  a  somewhat  difiieult  matter.  Tlie 
most  eoninioii  method  is  to  press  it  into  cakes,  which  greatly 
reduces  iis  l)ulk  and  makes  it  more  easily  handled.  These  are 
.sometimes  burned  but  are  more  often  used  for  fertilizing  purposes. 
In  some  causes  peat  or  other  absorbent  is  mixed  with  the  sludge 
and  the  whole  mass  removed  in  bulk.  In  other  instances  it  is  run 
out  on  the  surface  of  coarse  gravel  beds  and  reduced  by  draining 
and  drying.  In  wet  weather  little  drying  takes  place  and  during 
the  cold  months  the  sludge  accumulates  in  consideral)le  (|uantities. 
This  process  also  requires  considerable  manual  labor,  and  in  many 
Citscs  .suitable  land  is  not  available  for  the  purpose.  The  recjuiied 
capacity  of  the  settling  tanks  is  the  principal  item  ui  determining 
the^ost  of  installing  i)recipitation  works. 

In  the  treatment  of  house  sewage  provision  must  be  made  for 
alxiut  '^.^  the  total  daily  flow,  and  in  addition  to  this,  allowance 
must  be  made  for  throwing  out  a  pf)rtion  of  the  tanks  for  cleaning 


PLUMBING.  5T 


and  repairs.  In  general,  the  tank  capacity  should  not  be  much 
less  than  ^  the  total  daily  flow. 

In  the  combined  system  it  is  impossible  to  provide  tanks  for 
the  total  auiount,  and  the  excess  due  to  storm  water  must  dis- 
charge into  natural  water  courses  or  pass  by  the  works  without 
treatment. 

Broad  Irrigation  or  Sewage  Farming.  Where  sewage  is 
applied  to  the  surface  of  the  ground  upon  which  crops  are  raised 
the  process  is  called  "sewage  farming."  This  varies  but  little 
from  ordinary  irrigation  where  clean  water  is  used  instead  of 
sewage.  The  land  employed  for  this  purpose  should  have  a 
rather  light  and  porous  soil,  and  the  crops  should  be  such  as 
require  a  large  amount  of  moisture.  The  application  of  from 
5,000  to  10,000  gallons  of  sewage  per  day  per  acre  is  considered 
a  liberal  allowance.  On  the  basis  of  100  gallons  of  sewage  per 
head  of  population  this  would  mean  that  one  acre  would  care  for 
a  population  of  from  50  to  100  people. 

5ub-Surface  Irrigation.  This  system  is  employed  oidy 
upon  a  small  scale  and  chiefly  for  private  dwellings,  public  insti- 
tutions and  for  small  communities  where  for  any  reason  surface 
disposal  would  be  objectionable.  The  sewage  is  distributed 
through  agricultural  drain  tiles  laid  with  open  joints  and  placed 
only  a  few  inches  below  the  surface.  Provision  should  be  made 
for  changing  the  disposal  area  as  often  as  the  soil  may  require  by 
turning  the  sewage  into  sub-divisions  of  the  distributing  pipes. 

Intermittent  Filtration.  This  method  and  the  broad  irriga- 
tion already  described  are  the  only  purification  processes  in  use  on 
a  large  scale  which  can  remove  practically  all  the  organic  matter 
from  sewage  without  being  supplemented  by  some  other  method. 
The  process  is  a  simple  one  and  consists  in  running  the  sewage 
out  through  distributing  pipes  onto  beds  of  sand  4  or  5  feet  in 
thickness  with  a  system  of  pipes  or  drains  below  for  collecting  the 
purified  liquid.  In  operation  the  sewage  is  first  turned  on  one 
bed  and  then  another,  thus  allowing  an  opportunity  for  the  liquid 
portion  to  filter  through.  As  the  surface  becomes  clogged  it  is 
raked  over  or  the  sludge  may  be  scraped  off  together  witli  a  thin 
layer  of  sand.  The  best  filtering  material  consists  of  a  clean, 
sharp  sand  with  grains  of  uniform  size  such  that  the  free  space 


68  JMA-Mmx*;. 

K'tWivn  tlu'in  will  t'(|ii;il  almiit  oiic-thiid  llii'  total  voluim'.  When 
the  sewage  is  admittt'd  to  the  sand  oiilv  a  pai  t  of  the  ail-  is  driven 
out,  so  iheii'  is  a  store  ol  oxyt^en  K'tt  iH)on  wliieli  tiio  bacteiiii 
may  dr.iw.  Tliis  is  not  a  mere  jtroeess  of  strainiiitj^  l»ut  tlie  forma- 
tion of  new  eonipounds  l>y  the  action  oi  the  oxygen  In  the  air, 
thus  eliangiiig  the  organit'  matter  into  inorganic.  IVIuch  dej)ends 
upon  the  size  and  cjuality  of  the  sand  used.  The  grains  tliat  have 
Ik'i'U  found  to  give  the  best  results  range  from  .1  to  .5  of  an  incli 
in  diameter.  'I'he  work  done  hy  a  lilter  is  hirgely  determined  by 
the  iiner  jtartieles  of  sand  and  that  used  sliould  ))e  of  fairly  uni- 
form quality,  and  the  coarser  and  liner  particles  should  be  well 
mixed.  'J'he  an-a  and  volume  of  sand  or  gravel  required  are  so 
large  that  the  transportation  of  material  any  great  distance  cainiot 
l»e  considered.  Usually  the  beds  are  constructed  on  natural 
deposits,  the  top  soil  or  loam  being  removed.  The  sewage  sliould 
be  brought  into  the  beds  so  as  to  disturb  their  surface  as  little  as 
l)Ossible,  and  should  l)e  distributed  evenly  over  the  whole  bed. 

The  under  drains  should  not  be  placed  more  than  50  feet 
ajiart,  usually  much  less,  and  should  be  provided  with  manholes 
at  the  junctions  of  the  pipes.  Before  admitting  the  sewage  to  the 
beds  it  is  usually  best  to  screen  it  sufficiently  to  take  out  paper, 
rags  and  other  floating  matter.  The  size  of  each  bed  should  ])e 
sucli  as  to  permit  an  even  tlistribution  of  sewage  over  its  surface. 

Where  the  filtration  area  is  small,  it  must  be  divided  so  as  to 
permit  of  intermittent  operati(^ii ;  that  is,  if  a  bed  is  to  be  in  use 
and  at  rest  for  e([ual  periods,  then  two  or  more  beds  would  be 
necessary,  the  number  depending  on  the  relative  periods  of  use 
and  rest.  Some  additional  area  sliould  also  be  provided  foi-  emer- 
gency, or  for  use  while  the  beds  are  being  scraped.  If  a  large 
area  is  laid  out,  so  tliat  the  size  of  the  beds  is  limited  only  by 
convenience  in  use,  tlien  an  acre  may  be  taken  as  a  good  size. 

The  degree  of  purification  depends  upon  various  circum- 
stances, but  with  the  best  material  practically  all  of  the  oiganic 
matter  can  be  removed  from  sewage  by  intermittent  filtration  at  a 
rate  of  alx)ut  100,000  gallons  per  day. 

Theie  is  often  much  o[)position  to  sewage  purification  by 
these  living  or  owning  j)ropei-ty  near  tlie  jdants  ;  but  experience 
has  shown  that  well-conducted  jdants  are  inoffensive  botli  within 


PLUMBING.  50 


-and  witliout  their  enclosures.  The  employees  about  such  works 
are  as  healthy  as  similar  classes  of  men  in  other  occupations.  The 
crops  raised  on  sewage  farms  are  as  healthful  as  those  of  the  same 
kind  raised  elsewhere,  and  meat  and  milk  from  sewage  farms  are 
usually  as  good  as  when  produced  under  other  conditions.  Good 
design  and  construction,  followed  by  proper  methods  of  operation, 
are  all  tliat  are  needed  to  make  sewage  purification  a  success.  No 
one  system  can  be  said  to  be  the  best  for  all  localities.  The 
special  problems  of  each  case  must  be  met  and  solved  by  a  selec- 
tion from  among  the  several  systems  and  the  combinations,  of 
systems,  and  parts  chosen  that  are  best  adapted  to  the  conditions 

.at  hand. 


EXAni  NATION   PAPER. 


PLUMBING     PART  I. 


PLUMBING. 


Read  carefully  :  Place  your  name  and  full  address  at  the  head  of  the- 
naoer  Any  cheap,  light  paper  like  the  sample  previously  sent  you  may  be 
sed  Do  not  crowd  your"^ work,  but  arrange  it  neatly  and  legibly.  Do  not 
rovy\heanstcer.  from  the  Instruction  Paper:  me  your  oion  words,  so  that  loe 
Zl  heZTlhai  Uu  understand  the  subject.  After  completing  the  work  add 
and  sign  the  following  statement :  ,.     ,    , 

I  hereby  certify  that  the  above  work  is  entirely  my  own. 

(Signed) 


1.  What  causes  a  trap  to  "siphon,"*  and  in  what  tliree  ways- 

may  it  be  prevented  ? 

2.  What  size  of  soil  pipe  shoukl  be  used  for  an  ordinary- 
sized  dwelling,  and  wliat  pitch  should  be  given  to  the  horizontal 

portion? 

3.  What  quantity  of  water  per  capita  should  be  allowed  ni 

designing  a  sewerage  system  ? 

4.  What  form  of  cross-section  of  conduit  gives  a  maximum 
velocity  of  flow  to  small  quantities  of  sewage  ? 

5.  Describe  the  manner  of  making  house  connections  witb 

the  main  sewer. 

6.  Show  by  sketch   the    general  method    of  runnmg  the 
waste  and  vent  pipes  in  a  dwelling  house,  and  indicate  the  proper 

location  of  traps. 

7.  What  are  the  two  principal  methods  of  sewage  purifi- 
cation ? 

8.  Describe  the  method  of  making  up  the  joints  m  cast 

iron  soil  pipe. 

9.  In  what  way  may  the  seal  of  a  trap  be  broken  besides- 

siphonage  ? 

10.     What  two  tests  are  usually  given  to  a  system  of  plumb- 
ing?    State  the  use  of  each. 


04  ru'Miiixt;. 


II.  W'li.ii  ^'nitlc  slumld  lu>  cfivcti  to  iimiii  scweis  and 
liniiulii's  ■' 

1  *J.       (ii\r  two  iiu'tliods  {>i  lliisliiii'^  si'WiTS. 

lo.  Dt'scrilK'  brii'lly  soiiir  ol  llic  iisii;il  MnaiiLTciiioiiis  in  the 
j)lunil)iMi;  of  hotels. 

14.      What  is  sewaLjf  tanniiiijj?      Desciiht-  the  [)r()Ct'ss  l)ii('lly. 

1.").  What  is  the  diiVeieiice  between  a  "eup  joint"  and  a 
'•wipe  joint  .' "  State  the  eonditions  nndei-  which  yon  wonld  use 
eaeli. 

III.  What  is  tlie  use  of  a  flesh-air  inlet  in  eoiineetioii  with 
a  soil  Jfljie.  and  how   is  it  connected/ 

17.  Deserihe  the  ''Smoke  Test." 

18.  Should  a  tiap  of  lixtinc  he  vented  into  a  ehiinney  ? 
(rive  the  reasons  foi'  yonr  answer. 

10.  W'iiat  material  is  commonly  used  for  sewer  i)ii)es  of 
(litTerent  si/.es  / 

2U.  When  are  nnderdrains  reciuired  and  how  are  they  con- 
strncted '/ 

21.  What  ])recantions  should  be  taken  in  back  venting' 
ti-aps  ? 

'2'2.  What  iheniirals  are  commoidy  itsed  in  the  precipitation 
of  sewage  ? 

2o.  How  should  yon  coiniect  a  lead  pipe  with  a  cast  or 
^^TOU<^llt  iron  pipe  / 

24.  Define  the  "separate"  and  '•  cond)in('d  "'  systems  of 
sewerage. 

25.  What  is  the  principal  point  to  be  observed  in  the  dis- 
posal of  sewage?  What  precautions  should  Ije  taken  when  it  is 
discharged  into  a  stream? 

26.  What  is  tlie  sedimentation  process  ? 

-•.  What  precautions  should  be  taken  in  locating  a  cess- 
pool.'      Uescribe  Ijriefly  one  form  of  construction. 

'2H.  Name  some  of  the  most  important  data  to  be  obtained 
l^fore  laying  out  a  system  of  sewerage. 

20.  In  designing  a  system  of  surface  drains  what  maxinnim 
conditions  should  be   provided  for? 

80.  Under  wliat  conditions  may  sul>surface  irrigation  be 
used  to  advantage  ? 


PLUMBING 


PART     II. 


INSTRUCTION     PAPER 


AMERICAN      SCHOOL      OF      CORRESPONDENCE 

[cHA.RTERE:r>    BY    THK    COMMONWEALTH    OF    MASSACHUSKXTs] 

BOSTON,     MASSACHUSETTS 
U.   S.  A. 


Prepared  Bt 

Charles  L.  Hubbard,  M.E., 

OK 

S.  Homer  Woodbridge  Company, 
Heating,  Ventilation  and  Sanitary  Engineers. 


AmtHmn  School  0/  C0rresfi>f$dt^^r« 
Boston,  Mass. 


PLUMBING. 

PART  II. 

DOHESTIC  WATER  SUPPLY. 

Hydraulics  of  Plumbing.  Although  the  principles  of  Hy- 
draulics and  Hydrostatics  are  discussed  in  "  Mechanics,"  it  will 
be  well  to  review  them  briefly,  showing  their  application  to  the 
various  problems  uiuler  the  head  of  "  Water  Supply." 

If  several  open  vessels  containing  water  are  connected  by 
pipes,  the  water  will  eventually  stand  at  the  same  level  in  all  of 
them,  regardless  of  the  length  or  the  size  of  the  connecting  pipes. 

The  pressure  exerted  by  a  liquid  at  any  given  point  is  the 
same  in  all  directions,  and  is  proportional  to  the  depth. 

A  column  of  water  at  60°  temperature  having  a  sectional  area 
of  one  square  inch  and  a  height  of  one  foot,  weighs  .43  pound,  and 
the  pressure  exerted  by  a  liquid  is  usually  stated  in  pounds  per  square 
inch,  the  same  as  in  the  case  of  steam.  If  a  closed  vessel  is  con- 
nected, by  means  of  a  pipe,  with  an  open  vessel  at  a  higher  level, 
so  that  it  is  10  feet,  for  example,  from  the  bottom  of  the  first 
vessel  to  the  surface  of  the  water  in  the  second,  the  pressure  on 
each  square  inch  of  the  entire  bottom  of  the  lower  vessel  will  be 
10  X  -43  rr  4.3  pounds,  and  the  pressure  per  square  inch  at  any 
given  point  in  the  vessel  or  connecting  pipe  will  be  equal  to  its 
distance  in  feet  from  the  surface  of  the  water  in  the  upper  vessel 
multiplied  by  .43.  If  a  pipe  is  carried  from  a  reservoir  situated 
on  the  top  of  a  liill  to  a  point  at  the  foot  of  the  hill  a  luindred  feet 
below  the  surface  of  the  water,  a  pressure  of  100  X  .43  =:  43 
pounds  per  square  inch  will  be  exerted  at  the  lower  end  of  the 
pipe,  provided  it  is  closed.  When  the  pipe  is  opened  and  the 
water  begins  to  flow,  the  conditions  are  changed  and  the  pressure 
in  the  different  parts  of  the  pipe  varies  with  the  distance  from  the 
open  end. 

In  order  for  a  liquid  to  flow  through  a  pipe  there  must  be  a 
certain  pressure  or  "head"  at  the  inlet  end.  The  total  head  caus- 
ing  the    flow    is  divided  into  tliree  parts,    as    follows:    1st,    the 


I'LUMHLNG. 


iv/ofiV//  hoail :  llic  luMolit  tludiii^h  wliii-li  ;i  ImkIv  iiiiist  fall  in  a 
vacuuni  to  actiuiu'  tlic  vt'U>(.'ity  with  w  liidi  the  water  ciileis  thi^ 
pipe.  2i\,  {\\o  ttttri/  lu'a<l :  thai  ie([uiird  to  ovcrcoiiie  ilu'  lesist- 
anoe  to  onlnmce  into  tin'  pipe.  -'xL  the  fri-tion  head:  (hie  to  the 
frictional  ri'sistanee  to  How  within  the  |»iiie.  In  the  case  of  h>nor 
l>ipes  and  hiw  heads  tlie  sum  of  the  veloi-ily  :""1  entry  heads  is  so 
small  that  it  may  he  nenrleeted. 

Tahle  I  shows  the  pressure  of  water  in  pounds  per  sipuire 
ineh  for  elevations  varying  in  lieight  from  1  to  \'^b  feet. 

Table  II  gives  the  drop  in  piessnre  due  to  friction  in  pipes  of 
different  diameters  for  varviuij  rates  of  How.  The  fifuies  eriven 
are  for  pipes  lOO  feet  in  height.  The  frictional  resistance  in 
smooth  ]»ipes  having  a  constant  flow  of  water  through  them  is  pro- 
portional to  the  length  of  pi{)e.  That  is,  if  the  friction  causes  a 
drop  in  pressure  of  4.07  poimds  per  square  inch  in  a  l|-inch  pipe 
100  feet  long,  which  is  discharging  20  gallons  per  minute,  it  will 
cause  a  drop  of  4.07  X  2=8.14  pounds  in  a  pipe  200  feet  long  ;  or 
4.<>7  -^  2  =  2.03  pounds  in  a  pipe  oO  feet  long,  acting  under  the 
same  conditions.  The  factors  given  in  the  table  are  for  pipes  of 
smooth  interior,  like  lead,  brass  or  wrought  iron. 

Kxample. —  A  l;^-inch  pipe  100  feet  long  connected  Avith  a 
cistern  is  to  discharge  35  gallons  per  minute.  At  what  elevation 
alx)ve  the  end  of  the  pipe  must  the  surface  of  the  water  in  the 
cisteni  be  to  produce  this  flow? 

In  Table  II  we  find  tlie  friction  loss  for  a  1  i-inch  pipe  dis- 
charging 35  gallons  per  minute  to  be  5.05  pounds.  In  Table  I  we 
find  a  pressure  of  5.2  pounds  corresponds  to  a  head  of  12  feet, 
which  is  approximately  the  elevation  required. 

Ilftw  many  gallons  will  be  dischaiged  through  a  2-inch  pipe 
100  feet  long  where  the  inlet  is  22  feet  above  the  outlet?  In 
Table  I  we  find  a  head  of  22  feet  corresponds  to  a  pressure  of  9.53 
pounds.  Then  lr)oking  in  Talde  I  we  find  in  tiie  colunm  of  Fi-ic- 
tion  Loss  for  a  2-inch  pipe  that  a  pressure  of  9. 40  corresponds  to 
a  discharge  of  100  gallons  per  minute. 

Tables  I  and  II  are  commonly  used  together  in  examples. 

A  house  requiring  a  maximum  of  10  gallons  of  water  per 
minute  is  to  he  supplied  ivo\n  a  sj  /ing  wliich  is  looftted  600  feet 
distant,  and   at   an   elevation   of  50  feet  above   the  point  of  dis- 


PLUMBING. 


TABLE   I. 


Head 


Pressure 
pounds  per 
square   inch. 


1 

2 

3 

4 

5 

6 

7 

8 

9 
10 
11 
12 
13 
14 
15 
16 

17 

18 

19 

20 

21 

22 

23 

24 

25 

26 

27 

28 

29 

30 

31 

32 

33 

34 

35 

36 

37 

38 

39 

40 

41 

42 

43 

44 

45 


.43 
.86 
1.30 
1,73 
2.16 
2.59 
3.03 
3.46 
3.89 
4.33 
4.76 
5.20 
5.63 
6.06 
6.49 
6.92 
7.36 
7.79 
8.22 
8.66 
9.09 
9.53 
9.96 
10.39 
10.82 
11.26 
11.69 
12.12 
12.55 
12.99 
13.42 
13.86 
14.29 
14.72 
15.16 
15.59 
16.02 
16.45 
16.89 
17.32 
17.75 
18.19 
18.62 
19.05 
19.49 


Head 

in 

feet. 


46 

47 

48 

49 

50 

51 

52 

53 

54 

55 

56 

57 

58 

59 

60 

61 

62 

63 

64 

65 

66 

67 

68 

69 

70 

71 

72 

73 

74 

75 

76 

77 

78 

79 

80 

81 

82 

83 

84 

85 

86 

87 

88 

89 

90 


Pressure 
pounds  per 
square  inch. 


Head 


19.92 

20.35 

20.79 

21.22 

21.65 

22.09 

22.52 

22.95 

23.39 

23.82 

24.26 

24.69 

25.12 

25.55 

25.99 

26.42 

26.85 

27.29 

27.72 

28.15 

28.58 

29.02 

29.45 

29.88 

30.32 

30.75 

31.18 

31.62 

32.05 

32.48 

32.92 

33.35 

33.78 

34.21 

34.65 

35.08 

35.52 

35.95 

36.39 

36.82 

37.25 

37.68 

38.12 

38.55 

38.98 


Pressure 
pounds  per 
square  inch. 


91 

39.42 

92 

39.85 

93 

40.28 

94 

40.72 

95 

41.15 

96 

41.58 

97 

42.01 

98 

42.45 

99 

42.88 

100 

43.31 

101 

43.75 

102 

44.18 

103 

44.61 

104 

45.05 

105 

45.48 

106 

45.91 

107 

46.34 

108 

46.78 

109 

47.21 

110 

47.64 

111 

48.08 

112 

48.51 

113 

48.94 

114 

49.38 

115 

49.81 

116 

50.24 

117 

50.68 

118 

51.11 

119 

51.54 

120 

51.98 

121 

52.41 

122 

52.84 

123 

53.28 

124 

53.71 

125 

54.15 

126 

54.58 

127 

55.01 

128 

55.44 

129 

55.88 

130 

56.31 

131 

56.74 

132 

57.18 

133 

57.61 

134 

58.04 

135 

58.48 

ri.r.Mr.iNci. 


charcre.  What  size  of  pipe  will  ho  roquirod?  Frmn  Tal>l«'  I  we 
find  an  elevatitMi  or  lu'ad  of  AO  tret  will  product'  a  iircssmc  of  :il.G5 
pi>unds  j)i'r  sqnari'  iiu-li.  Tlu'ii  if  llic  length  of  tlu'  pipe  were 
onlv  100  foi'i.  wt'  sliould  li:i\('  a  jji-cssure  of  ill. •'».")  ])oiiiids  avail- 
able to  overoiMuo  the  friction  in  the  }>il>i',  andcoidd  foUow  along  the 
line  corresponding  to  10  gallons  in  Tahle  11  until  we    came  to  the 

TABLE  II. 


Jin. 

i 

n. 

1 

in. 

li 

in. 

11 

in. 

2 

n. 

21 

in. 

8  in. 

• 

h 

u 

h 

o. 

J" 

<u 

V 

0) 

0) 

0) 

•0 

Oi 

o. 

o. 

PU 

0. 

O. 

Q. 

s. 

o 

e 

w 

a 

H 

0) 

a 

01 

a 

4) 

0) 

n 

0) 
4> 

a 

<u 

fl 

a 

a  - 

■ 

s 

_0 

a 

a 
§ 

a 

(0 
(0 

o 

a 

n 
O 

0 

O 

a 

X 

a 

01 
01 

_0 

is 

»-  o 

>> 

fl   ■ 

>. 

a  ■ 

>. 

a  • 

>> 

fl    • 

>. 

fl    ■ 

>, 

a  ■ 

>. 

a  ■ 

S2 

o  a 
CS 

S.  o 
8.17 

5  o 

So 
a)  o 

.2-S 
.2§ 

h  P. 

J>  00 

.2^ 
P^  a. 

|1 
.2  o 

P*   00 

.2^ 

P»   00 

.2^ 

f^  P. 

^   00 

.2^ 
.2§ 

£a 

go 

.2^ 
.2S 

5 

24.6 

3.63 

3  3 

2.04 

.84 

1.31 

.31 

.91 

.12 

10 

16.3 

96.0 

7.25 

iS.O 

4.08 

3.16 

2.61 

105 

1.82 

.47 

1.02 

.12 

15 

10.9 

28.7 

6.13 

6.98 

3.92 

2.38 

2.73 

.97 

1.53 

.27 

20 

14.5 

.50.4 

8.17 

12.3 

5.22 

4.07 

363 

1.66 

204 

.42 

25 

18.1 

78.0 

10.2 

19.0 

6.53 

6.40 

4. ,54 

2.62 

2.55 

.67 

1.63 

.21 

1.13 

.10 

80 

12.3 

27.5 

7.8-1 

9.15 

545 

3.75 

3.06 

.91 

35 

14.3 

37.0 

9.14 

12  04 

6.36 

5.05 

3.57 

1.25 

40 

16.3 

48.0 

10.4 

16.10 

7.26 

6.52 

4.09 

1.60 

45 

11.7 

20.2 

8.17 

8.15 

4.60 

2.02 

60 

13.1 

24.9 

9.08 

10.0 

5.11 

244 

3  26 

.81 

2.27 

.35 

75 

19.6 

56.1 

13.6 

22.4 

7.66 

5.32 

4.90 

1.80 

3.40 

.74 

100 

18.2 

39.0 

10.2 

9.46 

6.53 

3  20 

4..54 

1.31 

125 

12.8 

14.9 

8.16 

4.89 

5.67 

1.99 

150 

15.3 

21.2 

9.80 

7.00 

'     6.81 

2.85 

175 

17.1 

28.1 

11.4 

9.46 

7.94 

3.85 

200 

20.4 

37.5 

13.1 

12.47 

9.08 

5.02 

friction  loss  corresponding  most  nearly  to  21.65,  and  take  the  size  of 
pipe  corresponding.  But  as  the  length  of  the  pipe  is  600  feet,  the 
friction  loss  will  be  six  times  that  given  in  Table  II  for  given  sizes 
of  pipe  and  rates  of  flow;  hence  we  must  divide  21.65  by  6  to  ob- 
tain the  available  head  to  overcome  friction,  and  look  for  this 
quantity  in  the  table,  21.65  -f-  6  =  3.61,  and  Table  II  .shows  us 
that  a  1-inch  pipe  will  discharge  10  gallons  per  minute  with  a 
friction  loss  of  -J. 16  j)0unds.  and  this  is  the  size  we  should  use. 

EXAHPLES   FOR   PRACTICE. 

1.     "What  size  pipe  will  be  required  to  discharge  40  gallons 
per  minute,  a  distance  of  50  feet,  with  a  pressure  head  of  19  feet? 

Ans.  1|  inch. 


PLUMBING. 


2.     What  head  will  be  required  to  discharge  100  gallons  per 
minute  through  a  2i-inch  pipe  700  feet  long? 

Ans.  52  feet. 


PIPING. 


Wrought  iron,  lead  and  brass  are  the  principal  materials 
used  for  water  pipes.  Wrought-iron  pipe  is  the  cheapest  and 
easiest  to  lay,  but  is  objectionable  on  account  of  rust  and  the 
consequent  discoloration   of  water  passing  through  it.     When  it 


TABLE  III. 


V 

o 

bo 

<u 

k< 

ri 

ti    Q\ 

a 

A 

s 

V 

g 

u 

a 

a 

a  o 

a 
'3 

V 

P. 

«o 

a 

.2 

s 

.2 
'5 

lU 

a 

i) 
S 

3 
o 

'o 

|5 

4) -a 

a 
o 
o 

*> 

•a 
ci    • 

0 

CO 

.9 

"3 

m 

ax) 

»H    O 

<u 

a 

4) 

3 

0 

.a  dj 

0 
0) 

o 

<u 

f-^ 

o^ 

o». 

? 

»o 

P. 

a. 

a 

"3 

a 

"3 

a 

a 

J30 

^o 

a 

52 

*> 
fl 

j2  ja 

m 

B 
o 

o 

2 

< 

a 

<0 

bX)0 

a  o 

a  o 

0) 

a 

"S 

3.2 

"3 
0 

in. 

in. 

in. 

in. 

in. 

in. 

feet 

feet 

in. 

in. 

feet 

pounds 

27 

.0006 

1 

.40 

.068 

.27 

.85 

1.27 

14.1 

9.44 

.05 

.13 

2500. 

.24 

18 

.0026 

J 

.54 

.088 

.36 

1.14 

1.69 

10.5 

7.05 

.10 

.23 

1385. 

.42 

18 

.0057 

i 

.67 

.091 

.49 

1.55 

2.12 

7.67 

5.65 

.19 

.36 

751.5 

.56 

14 

.0102 

* 

.84 

.109 

.62 

1.95 

2.65 

6.13 

4.50 

.30 

.55 

472.4 

.84 

14 

.0230 

i 

1.05 

.113 

.82 

2.59 

3.29 

4.63 

3.63 

.53 

.86 

270.0 

1.12 

llj 
Hi 

.0408 

1 

1.31 

.134 

1.05 

3.29 

4.13 

3.68 

2.90 

.86 

1.35 

166.9 

1.67 

.0638 

ii 

1.66 

.140 

1.38 

4.33 

5.21 

2.77 

2.30 

1.49 

2.16 

96.2 

2.26 

Hi 

llA 

.0918 

u 

1.90 

.145 

1.61 

5.06 

5.96 

2.37 

2.01 

2.04 

2.83 

70.6 

2.69 

.1632 

2 

2.37 

.154 

2.06 

6.49 

7.46 

1.85 

1.61 

3.35 

4.43 

42.3   j 

3.66 

8 

.2550 

'i^ 

287 

.204 

2.47 

7.75 

9.03 

1.54 

1.33 

4.78 

6.49 

30.1    \ 

5.77 

8 

.3673 

3 

3.50 

.217 

3.06 

9.63 

10.1 

1.24 

1.09 

7.39 

9.62 

19.5    : 

7.54 

8 

.4998 

^* 

4.00 

.226 

3. .55 

11.1 

12.5 

1.07 

.95 

9.88 

12.5 

14.5    j 

9.05 

8 

.6528 

4 

4.50 

.237 

402 

12.6 

14.1 

.95 

.85 

12.7 

15.9 

11.3 

10.7 

8 

.8263 

6 

5.56 

.259 

5.04 

15.8 

17.4 

.75 

.63 

20.0 

24.3 

7.2 

14.5 

8 

1.469 

6 

6.62 

.280 

6.06 

19.0 

20.8 

.63 

.57 

28.9 

34.4 

4.9 

18.7 

8 

1.999 

is  employed  for  this  purpose  it  is  customary  to  use  galvanized 
pipe,  that  is,  pipe  which  has  been  covered  with  a  thin  coating  of 
zinc  or  zinc  and  tin.  This  prevents  rust  from  forming  where  the 
zinc  is  unbroken,  but  at  the  joints  where  threads  are  cut,  and  at 
other  places  where  the  zinc  becomes  loosened,  as  by  bending,  the 
pipe  is  likely  to  be  eaten  away  more  or  less  rapidly,  depending 
upon  the  quality  of  the  water.  Zinc,  wlien  taken  into  the 
system,  is  poisonous,  and  for  this  reason  galvanized  pipes  should 
not  ordinarily  be  used  for  drinking  water. 


8 


rLl'.MlUNii. 


Tahlo  III  jxivi's  tlu'  various  dinuMisious  of  wroui^ht-iron  pipe. 
In  usin>;  pipe  of  tliis  kind,  it  is  well  to  allow  sonu'tliiiiu^  in  size 
for  possible  cliokiii«j^  by  rust  or  seilinu'ut.  While  galvanized 
pipe  ibu's  not  rust,  for  a  time  at  least,  there  is  likely  to  be 
a  roughness  wliieh  eauses  an  aeeuniulation  of  more  or  less 
sediment. 

TABLE   IV. 

Lead  Pipe. 


Int 

M 

H 

i 

.75 

.55 

1.00 

f 

.63 
1.10 

.84 
1.33 

3 
1 

.93 
1.60 

1 

1.18 

l4^ 

1.80 

H 

1.44 

H 

2.08 

n 

1.74 

n 

2.12 

n 

2.0 

2 

2.60 

2 

2.18 

.18 

.087 

.25 

.065 

.23 

.10 

.29 

.09 

.30 

.09 

.275 

.095 

.29 

.12 

.10 

.125 

.30 

.09 


1  lb.  12  oz. 
10 


s  s 


3 
1 
4 
1 
6 
1 
6 
2 
8 
3 
5 
3 
10 
4 


10 
8 
4 

14 
3 


12 


10 
11 


1968 

1085 

1787 

625 

1548 

708 

1462 

505 

1230 

325 

962 

322 

742 

245 

460 

318 

611 

200 


492 
271 
446 
156 
387 
177 
365 
126 
307 

81 
240 

80 
185 

61 
116 

79 
152 

50 


Iron  pipe  li..>.i.j4  .t  lining  of  tin  Jg  inch  or  more  in  thickness 
is  now  manufactured,  but  being  a  comparatively  new  product,  its 
wearing  qualities  have  not  yet  been  thoroughly  tested. 

Lead  Pipe  is  tlie  best  and  most  widely  used  for  domestic 
water  su[)ply.     Although  poisonous  under  certain   conditions,  as 


PLUMBING. 


when  new  and  bright  and  when  used  with  very  pure  water,  it 
usually  becomes  coated  with  a  scale  which  makes  it  practically 
harmless.  It  is  more  costly  than  iron  pipe,  and  requires  more 
skill  in  laying  and  making  up  the  joints.  It  is  less  likely  to  burst 
from  the  action  of  frost,  as  it  is  a  soft  metal  and  stretches 
with  the  expansion  of  the  ice  in  the  pipe.  When  it  does 
break  under  pressure  it  generally  occurs  in  small  holes  not 
over  an  inch  long,  which  are  easily  repaired  without  removing 
any  part  of  the  pipe,  while  in  the  case  of  iron  pipe  the  cracks 
generally  extend  the  entire  length  of  the  section  in  which  the 

TABLE  V. 

Tin-lined  Lead  Pipe. 


u 

a 

g 

1 

M 

o 
o 

<°' 

'S 

■1^ 
o 
o 

A 

'3 

o 
o 

u 

<^ 

A 
bo 
'3 

o 
o 

u 

A 
'3 

o 
o 

u 

A 
SO 

'3 
lb.    oz. 

o 
o 

'3 

o 

.Syp. 
'3 

o 

o 

u 

■    <o 

A 
'3 

o 

o 

.^  u 
A  <u 
MP. 

^A 

lb.    oz. 

lb.    oz. 

lb.    oz. 

lb.    oz. 

lb.    oz. 

lb.  oz. 

lb.    oz. 

lb.  oz. 

1      8 
3      0 

3  8 

4  8 

1  5 

2  0 

2  12 

3  8 

1      2 

1  12 

2  8 

3  0 

1      0 

1  4 

2  0 
2      4 

0  13 

1  0 

1  12 

2  0 

0    10 

0  13 

1  8 
1     12 

1    4 
1    8 

0      8 

0  11 

1  0 
1      4 

1  8 

2  0 

3  4 

0      9 

0  12 

1  0 

i' 

6      0 

4    12 

4      0 

3      4 

2      8 

2      0 

1^ 

6    12 

5    12 

4    12 

3    12 

3      0 

2      8 

I' 

9      0 

8      0 

6      4 

5      0 

4      4 

3      8 

10    12 

9      0 

7      0 

6      0 

5      4 

4      0 

water  is  frozen,  and  new  pipe  will  be  required.  Lead  pipe 
is  commonly  made  in  six  different  thicknesses  or  weights,  desig- 
nated as  AAA,  AA,  A,  B,  C  and  D,  in  which  AAA  is  the 
heaviest  and  D  the  lightest.  Table  IV  gives  the  principal  prop- 
erties of  the  heaviest  and  lightest  weight  for  lead  pipe  of  different 
diameters. 

Tin-lined  lead  pipe  is  used  to  some  extent  for  conveying 
water  for  domestic  purposes.  Tlie  principal  objection  to  this  pipe 
lies  in  the  difficulty  experienced  in  making  the  joints.  Tin  melts 
at  a  considerably  lower  temperature  than  lead,  so  that  in  making 
wipe  joints  it  is  likely  to  melt  before  the  lead  and  block  up  the 
passage  through  the  pipe.     Another  objection  is  due  to  the  fact 


10 


ri.rMr.iNi;. 


thai  ihe  tin  lininq:  nm\  the  outtM-  lead  coverini,''  aiv  simply  pressed 
togotluT,  and  it  olti'ii  happens  tliat  in  In'mling  the  pipe  the  linino- 
pulls  away  from  the  lead  thns  Ixah  ohstruetinij:  and  Aveakening 
the  jiipe.  When  used  for  hot  Avater,  the  uneven  expansion  of  the 
two  metals  may  separate  the  tAvo  layei-s,  and  so  cause  the  same 
difliculties  already  mentioned. 

Table  \'  gives  some  of  the  pro})erties  of  tin-lined  lead  j)ipe. 


Fijr.  2. 


The  strength  of  tin-lined  pipe  is  about  the  same  as  that  of  lead 
pipe,  the  greater  strength  of  the  tin  being  offset  by  the  lighter 
weight  of  the  pipe  made  in  this  way. 

Brass  Pipe.  P>rass  is  one  of  tlie  best  materials  for  hot- 
water  i»ipes,  and  should  be  used  where  the  cost  is  not  the  control- 
ling feature.  It  is  commonly  employed  for  connecting  pumps  and 
boilers  and  for  the  steam-heating  coils  inside  laundiy-water 
heaters.  It  is  often  used  for  the  connections  between  the  kitchen 
hot-water  tank  and  range,  and  when  nickel  plated  is  extensively 
employed  in  connection  with  bathroom  fixtures.  The  sizes  and 
thicknesses  are  approximately  tiie  same  a,s  wrought-iron  jjipe. 


PLUMBING.  11 


punps. 

The  principle  upon  which  the  pump  operates  has  ah-eady 
been  taken  up  in  the  Instruction  Paper,  "  Mechanics."  The 
more  common  forms  are  known  as  the  "Uft  pump,"  the  '-suction 
pump"   and    a    combination   of   the   two    called    the    "deep   well 

pump." 

Fig.  1  shows  a  pump  of  the  first  kind.  In  this  pump  A  is 
the  cylinder,  B  the  plunger,  C  the  Ijottom  valve  and  D  the 
plunger  valve.  When  the  plunger  is  drawn  up,  a  vacuum  is 
formed  in  the  cylinder,  and  water  flows  in  through  C  to  fill  it. 
When  the  plunger  is  forced  down,  valve  D  opens  and  allows  the 
water  to  flow  through  the  plunger  while  C  remains  closed.  As 
this  operation  is  repeated,  the  water  is  raised  by  the  plunger  at 
each  stroke  until  the  entbe  length  of  the  pump  barrel  is  filled, 
and  it  will  then  flow  from  the  spout  in  an  intermittent  stream. 

In  the  suction  pump  shown  in  Fig.  2,  the  cylinder  and  valves 
are  the  same,  but  they  are  placed  at  the  top  of  the  Avell  and  are 
connected  with  the  water  below  by  means  of  a  pipe,  as  shown. 
When  the  pump  is  operated,  a  vacuum  is  formed  in  the  cyUnder 
and  pipe  below  the  plunger,  and  the  pressure  of  the  atmosphere 
upon  the  surface  of  the  water  forces  it  up  the  pipe  and  fills  the 
chamber,  after  which  the  action  becomes  the  same  as  in  the  case 
of  a  lift  pump.  The  pressure  of  the  atmosphere  is  approximately 
15  pounds  per  square  inch,  which  corresponds  to  the  weight  of  a 
column  of  water  34  feet  high,  which  is  the  height  that  the  water 
may  be  raised  theoretically  by  suction. 

When  the  surface  of  the  water  is  a  greater  distance  than  this 
below  the  point  of  discharge,  a  pump  similar  to  that  shown  in  Fig. 
3  must  be  used.  A  is  a  cylinder  with  plunger  and  valves  similar 
to  those  of  a  suction  pump.  The  cyhnder  is  supported  in  the  well 
at  some  point  less  than  34  feet  above  the  surface  of  the  water  ;  E 
is  an  air  chamber  connecting  with  the  upper  part  of  the  pump 
cylinder,  and  F  a  discharge  pipe  leading  from  the  bottom  of  the 
air  chamber  E.  The  action  is  as  follows :  water  is  pumped  into 
the  bottom  of  the  air  chamber,  and  as  it  rises  and  seals  the  end 
of  the  discharge  pipe,  the  air  in  the  upper  part  of  the  chamber 
is  compressed,  and  as  soon  as  sufficient  pressure  is  obtained  the 
water  is  forced  out  through  the  discharge  pipe  F.     The  pressure 


12 


PLUM  HI  \(;. 


reijuiivil  in  the  air  ihaniltci-  di'itciids  upnii  the  lit'iij;-ht  to  whicli  the 

water  is  raised. 

The    Hydraulic    Ram.       This   is    a    device    for    automatically 

n\ising  water  from  a  lower  to  a  hi<jflier  level,  the  only  requirements 

within  certain  limits  heing  that 
the  ram  shall  he  placed  at  a  given 
distance  from  the  spring  or  source 
of  supply  and  at  a  lower  level, 
depending  upon  the  height  to 
which  the  Avater  is  to  be  raised 
and  the  length  of  thepipe  through 
which  it  is  to  be  forced.  The 
distance  from  the  source  or 
spring  to  the  ram  should  be  at 
least  from  25  to  50  feet,  in  order 
to  secure  the  recjuired  velocity 
for  proper  operation.  A  differ- 
ence in  level  of  2  feet,  or  even 
less,  is  sufficient  to  operate  the 
ram  ;  but  the  greater  the  differ- 
ence, the  more  powerful  is  its 
ojjeration.  For  ordinary  pur- 
poses, Avhere  the  water  is  to  be 
conveyed  from  50  to  GO  rods, 
about  -^^  to  -j^^  of  the  total  amount 
used  can  be  raised  and  dis- 
charged at  an  elevation  ten 
times  as  great  as  the  fall  fiom 
the  sj)ring  to  the  ram. 

In     Fig.    4,    A    represents 


Fig.  3. 


the  source  or  spring,  B  the  supply  pipe,  C  a  valve  opening  up- 
ward. D  an  air  chamber,  K  a  valve  closing  when  raised,  and  F 
the  discharge  pipe,  ^^'ilen  the  water  in  the  pipe  is  at  rest, 
the  valve  E  drops  by  its  own  weight  and  allows  the  water 
to  flow  through  it.  As  soon  as  a  sufficient  velocity  is  reached 
by  the  water,  its  momentum  or  force  raises  the  valve  against  its 
seat  and  closes  it.      The  water  being  thus  suddenly  arrested  in  its 


PLUMBING. 


13 


passage  flows  into  the  chamber  D,  where  its  sudden  influx  com- 
presses the  air  in  the  top  of  the  chamber,  and  this  in  turn  forces 
the  water  upward  through  the  discharge  pipe  F.  As  soon  as  the 
water  in  the  pipe  B  becomes  quiet,  the  valve  E  again  opens  and 
the  operation  is  repeated.  Bends  in  either  the  drive  or  discharge 
pipe  should  be  avoided  if  possible.  If  elbows  are  necessary,  the 
extra  long  turn  pattern  should  be  used  in  order  to  give  as  little 
resistanc^  as  possible.     These   machines   are   made   of  iron  and 


=^ 


COPPCR - 
LINING 


^ 


TIE.  ROD 

Fig.  5. 


Fig.  4. 

brass.  The  valve  and  stem  are  of 
bronze,  on  account  of  its  wear- 
ing qualities. 

Cisterns  and  Tanks.  Water 
cisterns   and   tanks  are    made   of 
various  materials  and  in  different 
shapes   and   sizes,    according   to 
the   special  uses   for  which  they   are  required.       A  durable     and 
satisfactory   tank  may  be    made    of   heavy  woodwork   or   plank 
bolted  together  with  iron  rods  and  nuts  and  then  lined  with  some 
sheet  metal,  such  as  copper,  lead  or  zinc.     Copper  or  lead  makes 
the  best  lining,  as  the  zinc  has  a  greater  tendency  to  corrode  and 
become  leaky.     If  copper  is  used,  it  should  be  tinned  on  the  out- 
side.    Fig.  5  shows  a  wooden  tank  in  plan,  with  the  method  of 
locking   the   joints  in    the  copper  .lining.     All   nails   should    be 
so  placed  as  to  be  covered  by  the  copper,  and  the  joints  soldered 
with  the  best  quality  of  solder,  which  should  be  allowed  to  souk 
into  the  seams.     If  the  tank  is  lined  with  lead,  a  good  weight 


14 


riAMlilNG. 


sliouKl  l>o  ust'il  (:il)out  six  jiouiids  per  siiuaro  foot)  aiitl  the  joints 
(.MivluUy  wipoil  hy  an  ('\[)t'iioiu'('tl  workman.  If  u.seil  for  the 
Bttu-ago  of  drinking;  water,  tliis  form  of  linintjf  is  o[K'n  to  the  same 
objorti«»ns  as  U'ad  pipe,  hut  if  kept  lilh'd  at  all  times,  and  esjie- 
cially  if  the  water  eontains  mineral  matter  to  any  extent,  tlien^  is 
very  litth'  danjxer,  as  a  eoatino-  is  soon  foi'ined  over  the  snrface  of 
tlie  lead,  protecting  it  from  the  action  of  the  water. 


Fiti.  d. 


Cast-iron  sectional  tanks  can  be  had  in  almost  any  size  or 
shape.  A  tank  of  tliis  form  is  shown  in  Fig.  G.  It  is  made  up  of 
plates  which  are  planed  and  holted  together,  the  joints  being  made 
tight  with  cement.  The  sections  are  made  in  convenient  sizes,  so 
that  they  may  be  handled  easily  and  conveyed  without  difficulty 
through  small  openings  to  any  part  of  the  house.  These  tanks 
are  easily  set  up,  and  are  practically  indestructible.  Wrought- 
iron  tiinks  aie  often  used,  but  are  not  as  easily  liandled  as  eitlier 
of  the  kinds  just  described.  Table  VI  will  be  found  useful  in 
computing  the  size  of  cylindrical  tanks. 


COLD-WATER    SUPPLY. 

Systems.  There  are  two  general  methods  of  supplying  a 
buihbng  with  watei",  one  knoAvn  as  the  "direct  supply  "  system, 
and  the  other  as  tlie  "indirect"  or  "  tank"  system. 

In  the  direct  system  each  fixture  is  connected  with  the 
su[)ply  pipe  and  is  under  the    same  pressure  as  the  street  main, 


PLUMBING. 


15 


unless  a  reducing  valve  is  introduced.  This  system  is  not  always 
desirable,  as  the  street  pressure  in  many  places  is  likely  to  vary, 
especially  where  the  water  is  pumped  into  the  mains.  A  variable 
pressure  is  injurious  to  the  fixtures,  causing  them  to  leak  much 
sooner  than  if  subjected  to  a  steady  pressure.  Where  the  pres- 
sure in  the  street  main  exceeds  40  pounds  per  square  inch,  a 
reducing  valve  should  be  used  if  the  direct  system  is  to  be 
employed. 

TABLE  VI. 

Capacity  of  Cisterns,  in  Gallons,  for  each  10  inches  in  Depth. 


Diam- 
eter in 
feet. 

Gallons. 

Diam- 
eter in 
feet. 

1 

Gallons.     ' 

Diam- 
eter in 
feet. 

Gallons. 

2.0 

19.5 

6.0 

176.3 

10 

489.6 

2.5 

30.5 

6.5 

206.8 

11 

592.4 

3.0 

44.6 

7.0 

239.9 

12 

705.0 

3.5 

60.0 

7.5 

275.4 

13 

827.4 

4.0 

78.3 

8.0 

313.3 

14 

959.6 

4.5 

99.1 

8.5 

353.7 

15 

1101.6 

5.0 

122.4 

9.0 

396.5 

20 

1958.4 

5.5 

148.1 

9.5 

461.4 

25 

3059.4 

The  following  factors  for  changing  a  given  quantity  of  water 
from  one  denomination  to  another  will  often  be  found  useful  : 

Cubic  feet  X  62^  =  Pounds 
Pounds  -^-  62|-  =  Cubic  feet 
Gallons  X  8.3  =  Pounds 
Pounds  -r-  8.3  =  Gallons 
Cubic  feet  X  7.2  =  Gallons 
Gallons       -5-  7.2  =  Cubic  feet 

For  domestic  purposes  the  indirect  system  is  much  better. 
In  this  case  the  connection  with  the  street  main  is  carried  directly 
to  a  tank  placed  in  the  attic  or  at  some  point  above  the  high- 
est fixture,  and  all  the  water  used  in  the  house  discharged  into 
it.  The  supply  of  water  is  regulated  by  a  ball-cock  in  the 
tank  which  shuts  it  off  when  a  certain  level  is  reached.  All  the 
plumbing  fixtures  are  supplied  from  the  tank,  and  are  therefore 


IG 


I'M  -MIUNG. 


iimlor  a  oonstaiii  {avssuiv.  This  pressuro  dt'iu'iuls  u|)()ii  tlic  dis- 
tance of  the  tixtmv  hi-low  the  tank.  'I'hc  iiipcs  and  lixluics  in  a 
house  supplied  with  the   tank  svstcni   will   last  niucli   lonocr  and 


\  I 


TO  RANGE  BO/LER 


SERV/CE 
P/PE 


Fig.  7. 


give  much  better  results  than  if  connected  directly  with  the  street 
main.  The  tank  is  also  found  usefid  for  storage  purposes  in  case 
of  repairs  to  the  street  mains,  wliich  is  often  a  matter  of  much 
inconvenience. 

Fig.  7  shows  the  general  arrangement  of  the  cold-water  pipes 
of  an  indirect  supply  system.     On  the  right  is  shown  the  service 


PLUMBING. 


17 


pipe,  wbicli  is  carried  directly  from  the  street  to  the  attic,  and 
then  connected  with  a  ball-cock  located  inside  the  house  tank. 
A  supply  pipe  is  taken  from  the  bottom  of  the  tank  and  carried 
downward  through  the  building  for  supplying  the  various  fixtures. 
A  stopcock  should  be  placed  in  the  supply  pipe  for  closing  off 
the  tank  connections  in  case  of  repairs  to  the  house-piping  or 
fixtures. 

Tank  Overflow  Pipe.  In  order  to  prevent  any  possibility 
of  overflow,  every  house  tank  should  be  supplied  with  an  overflow 
pipe  of  sufficient  size  to  carry  off  easily  the  greatest  quantity  of 
water  that  may  be  discharged  into  it.  The  overflow  from  a  house 
tank  should  never  be  connected  directly  with  a  sewer  or  soil  pipe, 
even  if   provided    with  traps,   for   the    water  may   seldom    flow 


CELLAR 


wmw^ 


Fig.  8. 


through  this  pipe,  thus  allowing  the  trap  to  become  unsealed 
through  evaporation.  It  is  much  better  to  let  the  end  of  the 
overflow  pipe  be  open  to  the  atmosphere  or  drop  over  some  fixture 
which  is  in  constant  use. 

Service  Pipe  Connections.  Fig.  8  shows  the  usual  method 
of  connecting  the  service  pipe  with  the  street  main.  The  service 
cock  is  connected  directly  with  the  main,  and  should  be  carefully 
blocked,  so  that  any  pressure  of  earth  from  above  will  not  break 
the  connection  or  strain  the  cock.  To  do  this  properly,  the  earth 
under  the  pipe  should  be  rammed  down  solid  after  the  connections 
are  made,  and  the  pipe  at  this  point  should  be  supported  on  sound 


18 


ri.iMr.iN'G. 


CELLAR 


I 


^ 
^ 


r^/- 


^^ 


wooden  Mocks.  If  ij[jilv;uii7AHl  iron  is  used  for  the  service  pipe,  it 
should  iu  all  oases  Ik'  eoniu't'ted  to  the  main  service  cock  with  a 
short  piece  of  lead  pipe  two  or  three  feet  lonr^,  for  the  reason  that 
lead  will  ijivt'  (U-  sai,'  w  ith  the  pressure  of  tiie  earth  without  break- 
iui^.  The  renuiinder  of  the  {»ipe  should  be  carefully  embedded  in 
the  earth,  to  prevent  uneven  strains  at  any  paitieular  point. 
Connections  between  the  lead  and  iron  pipes  should  be  made  by 
means  of  brass  ferrules  and  wiped  joints.  A  stopcock  should 
be  placed  in  the  service  pipe  just  inside  the  cellar  wall,  and  in  a 
position  where  it  will  be  accessible  in  case  of  accident.  A  drip 
should  be  connected  with  the  stopcock  for  drainin<j^  the  pipes 
when  water  is  shut  otY. 

In  protecting  pipes  against 
freezing  it  is  well  to  pack  them 
in  hair,  felt,  granulated  cork  or 
dry  shavings  where  they  pass 
through  the  floor.  This  is  shown 
in  Fig.  8.  AVhen  the  service 
pipe  comes  in  below  the  cellar 
floor,  it  may  be  arranged  as  shown 
in  Fig.  9.  The  cock  should  be 
placed  about  18  inches  below  the 
cellar  bottom  in  a  wooden  box 
with  hinged  cover,  so  that  it 
may  be  easily  reached. 
In  many  cities  and  in  certain  elevated  situations  the  pres- 
sure in  the  mains  is  not  sufficient  to  carry  the  water  to  the 
house  tanks  in  the  attics  of  the  higher  buildings,  and  it  becomes 
necessary  to  use  some  form  of  automatic  pump  for  this  purpose. 
The  screw  pump  shown  in  Fig.  10  is  especially  adapted  to  uses  of 
this  kind  when  equipped  with  an  electric  motor  and  automatic 
starting  and  stopping  devices.  A  float  in  the  tank  operates  an 
electric  switch  b}'  means  of  a  chain  and  weights,  as  sho^vll.  A 
centrifugal  or  rotary  pump  is  also  satisfactory  for  this  work. 

Another  device  which  may  be  attached  to  a  steam  pump  is 
shown  in  Fig.  11.  When  the  water  line  in  the  tank  reaches 
a  given  height,  the  float  closes  a  butterfly  valve  in  the 
discharge    pipe,    thus   increasing    the    pressure    within     it;     this 


SERVICE   PIPE 


f 


Fig.  9. 


PLUMBING. 


19 


in  pressure  acts  on  the  bottom  of  a  piston  by  means  of  a  connect- 
ing  pipe,  and  in  raising  the  piston,  shuts  off  the  steam  supply  to  the 
pump.     When  the  water  line  in  the  tank  is  lowered,  the  float  falls 

and  the  butteifly  valve 


opens,  relieving  the  pres- 
sure in  the  pipe  and  al- 
lowing the  steam  valve  to 
open  by  the  action  of  the 
counterweights  attached 
to  the  lever  arm  of  the 
valve,  as  shown.       The 
automatic  valve  is  shown 
in  section   in    Fig.    12. 
Another  means  of  rais- 
ing water    to  an  eleva- 
tion for    domestic  pur- 
poses, especially  in   the 
country,  is  by  the  use  of 
a    windmill.       A    large 
storage  tank  is  placed  at 
a  suitable  height  so  that 
a  sufficient  supply  may 
be    pumped    on    windy 
days  to  last  over  inter- 
vening  periods  of  calm 
weather. 

HOT=WATER  SUPPLY. 

All  modern  systems 
of  plumbing  include  a 
hot-water  supply  to  the 
various  sinks,  bowls, 
bathtubs  and  laundry- 
tubs  throughout  the 
house. 

Fig.  13  shows  the  usual  arrangement  of  a  kitchen  boiler  and 
water-back   with  the  necessary  pipe  connections.     The  boiler  is 


FROM  i ,_^ij 


l^OTOR 


20 


ri.iMr.ixG, 


Fig.  11. 


PLUMBING. 


21 


commonly  made  of  copper  and  supported  upon  a  cast-iron  base. 
It  may  be  located  in  the  kitchen  near  the  range,  or  may  be 
concealed  in  a  nearby  closet.  The  "water-back/'  so  called,  is 
a  special  casting  placed  so  as  to  form  one  side  of  the  fire  box  in 


BLOW- OFF  COCf<\ 
Fior.  12. 


the  range.  The  cold-water  supply  pipe  to  the  boiler  usually 
enters  at  the  top  and  is  carried  down  to  a  point  near  the  bottom, 
as  shown  by  the  dotted  lines.  Connection  is  made  between  the 
bottom  of  the  boiler  and  the  lower  chamber  of  the  water-back.  The 
upper  chamber  is  connected  at  a  point  about  one-third  of  the  way 
up  in  the  side  of  the  boiler,  as  shown.     The  circulation  of  water 


22 


PLUM1JIN(;. 


ilnoiiLih  llio  boiler  and  supply  pipes  is  the  same  ;i.s  already  de- 
M  rilit'd  for  iiot-watiT-liiMiiiii^  systems,  'i'lic  raiiu^e  fire  in  t-ontact 
with  tlu'  watcr-bai'k  lirats  tlic  watfr  williin  il,  which  causes  it  to 
rise   throuL'h    the    jiipc    coiuu'cti'd    with    the    upper   eiiamber   and 


HOT  \AJf\T£fi    TO  BC//LO//VG 


Fig.  13. 


flow  into  the  boiler  or  tank ;  in  the  meantime  cooler  water  flow8 
in  at  tlie  lower  connection  to  take  its  place,  and  the  circulation 
thus  set  up  is  constant  as  long  as  there  is  a  iiie  in  tlie  range. 

The  "boiler,"  so  called,  is  not  a  heater,  but  only  a  storage 
tank.  As  the  water  becomes  heated  it  rises  to  the  top  of  tiie  tank 
and  is  carried  to  the  different  fixtures  in  the  building  through  a 
pipe  or  pipes  connected  at  this  point.  The  cold-water  supply  pipe 
is  connected  with  the  house  tank  so  that  the  pressure  in  the  boiler 


PLUMBING. 


2a 


is  that  due  to  the  height  of  the  tank  above  it.  When  any  of  the 
hot-water  faucets  are  open,  the  pressure  of  the  cold  water  in  the 
supply  pipe  forces  out  the  hot  water  at  the  top  of  the  boilers 
and  rushes  in  to  take  its  place.  There  is  no  connection 
between  the  circulation  through  the  water-back  and  the  pressure 
in  the  cold-water  supply  pipe.  The  circulation  is  due  only  to  the 
difference  in  temperature  be- 
tween the  water  in  the  pipe 
leading  from  the  top  of  the 
water-back  and  the. water  in 
the  lower  part  of  the  boiler, 
and  difference  in  elevation  of 
the  connections  with  the 
boiler.  The  nearer  the  top  of 
the  boiler  the  discharge  from 
the  water-back  is  connected,  j^pSr 
the  more  rapid  will  be  the  blow-off 
circulation  and  the  greater 
the  quantity  of  water  which  Fig.  14. 

will  be    heated    in    a    given 

time.  The  cold-water  supply  simply  furnishes  a  pressure  to  force 
the  hot  water  through  the  pipes  to  the  different  fixtures,  and  re- 
places any  Avater  that  is  drawn  from  the  boiler. 

Care  should  always  be  taken  to  have  the  pipes  between  the 
water  back  and  the  boiler  free  from  sediment  or  any  other  ob- 
struction.    If  the  water-back  from  any  cause  should  become  shut 
off  from  the  boiler,  an  explosion  would  be  likely  to  occur  if  there 
was  a  hot  fire  in  the  range.     Freezing  of  the  pipes  is  sometimes  a 
cause  of  accident.      The  sediment  which  accumulates  more  or  less 
rapidly  should  be  regularly  blown  off  through  the  blow-off  cock 
provided  for  this  purpose  at  the  bottom  of  the  boiler.     The  best 
time  for  doing  this  is  in  the  morning,  before  the  fire  is  started. 
The  device  shown  in  Fig.  14  is  intended  to  prevent  the  sediment 
from  collecting  in  the  pipes  or  from  being  drawn  into  the  water- 
back,  making  the  water  roily  when  a  large  amount  is  drawn  off  at 
one  time.     It  consists  of  a  small  cylinder  or  chamber  connected 
to  the  bottom  of  the  boiler  in  such  a  way  that  the  sediment  will 
fall  into  it  and  not  be  disturbed  by  the  circulation   of  the  water 
through  the  pipes. 


24 


iM.rMuiNt;. 


Double  Water-back  Connections.  It  is  ofU'u  dosiiable  to 
ooniii'ct  :i  hoiK'i-  wilh  Iwo  w  atci-ltacks,  (Hif  in  tlic  kitchen  range 
anil  another  in  a  lanndiy  stove  in  thi'  eellar  for  summer  use. 
Vig.  15  shows  the  common  method  of  making  the  connections. 
In  tliis  case  cither  may  be  used  separately,  or  l)otli  together  with- 
out any  adjustment  of  valves.     The  blow-off  cock  at  the  bottom 


i  1 


^Ja=^^ 


utt: 


"1 


\Aars/f-aac^ 


^2t=^ut:i: 


kv*i7-ir/?-5>acA 


Fi-.  i: 


of  the  lower  water-back  should  be  opened  quite  often  to  clear  it 
of  sediment,  as  il:  will  collect  much  faster  at  this  point  than  at  the 
bottom  of  the  boiler. 

Double  Boiler  Connections.  It  quite  frequently  happens  that 
the  kitchen  boiler  does  not  have  sullicient  capacity  for  the  entire 
house,  and  it  is  not  desirable  to  use  a  larger  boiler  on  account 


PLUMBING. 


25 


of  the  limited  space  in  the  kitchen.     In  such  cases  a  second  boder 

may  be  connected  with  the  laundry  stove  if  one  is  provided,  and 

the  Avater  pipes  from  both  boilers  be  connected  together  at  some  point 

so    that  they  may 

both  discharge  hot 

water  into  the  same 

general  supply. 
Stopcocks  should 

be    placed  in    the 

pipe  connections  as 

shown,    so     that 

either  boiler    may 

be     shut    off     for 

repairs  without  in- 
terfering with  the 
operation     of    the 
other.  Waste  cocks 
should    always    be 
used  for  this  pur- 
pose, so  that  when 
closed   there     will 
be  a  connection  be- 
tween   the    boiler 
and     the      atmos- 
phere.    This    will 
prevent  damage  to 
the  boiler  in   case 
those     in     charge 
should     forget    to 
open      the      cocks 
when  starting  up  a 
fire   in    the    stove 
with     which      the 
boiler  is  connected. 


Fig.  16. 


Circulation  Pipes.  It  is  often  desirable  to  produce  a  con- 
tinuous circulation  in  the  distributmg  pipes  so  that  hot  water  may 
be  drawn  from  the  faucets  at  once,  without  waiting  for  the  cooler 
water  in  the  pipe  between  the  boiler  and  the  faucet  to  run  out. 


26 


i'i.rMHi\(;. 


This  is  accomplished  by  connectini,'  ;i  small  jiipe  with  the  liot- 
water  pipe  near  the  faucet,  and  connecting  it  \vitli  the  bottom  of 
the  boiU'i-  as  shown  in  Fig.  17.  This  makes  a  circuit,  and  a  con- 
stant circulaiion  is  })roihu'e4  by  tlie  dilTerenco  in  temperature  of 
tlie  water  in  the  supply  ami  cireiilalion  pipes. 


COLD  V^TCfK    SL/Pfity 
f»OM  HOUSC  TANn 


FiL'.  i; 


P.ipe  Connections*  lirass  or  copper  pipe  with  screwed  fit- 
tings should  always  be  used  for  making  the  connections  between 
tlie  bfjiler  and  water  back.  Where  unions  are  used  they  should 
have  ground  joints   without   packing.     Lead  pipe   is   too  soft  to 


PLUMBING. 


27 


stand  the  high  temperature  to  which  these  pipes  are  sometimes 

subjected.  - 

Laundry  Boilers.  In  laundries,  hotels,  etc.,  where  a  large 
amount  of  hot  water  is  used,  it  is  necessary  to  have  a  larger 
storage  tank  and  a  heater  with  more  heating  surface  than  can  be 


HOT  WATER    P/PCS 


Fig.  18. 


Fig.  18    shows   an 


obtained  in  the  ordinary  range  water-back, 
arrangement  for  this  purpose. 

The  boiler  may  be  of  wrought  iron  or  steel  of  any  size  de- 
sired, and  is  usually  suspended  from  the  ceiling  by  means  of 
heavy  strap  iron.  The  heaters  used  are  similar  to  those  employed 
for  hot  water  warming.  The  method  of  making  the  connections 
is  indicated  in  the  illustration. 


28 


I'Ll.MlilNG. 


Tlie  capacity  of  the  heater  and  tank  depends  entirely  ujjon 
the  amount  of  water  useil.  In  some  easi's  a  lari^o  storaj^e  tank 
iuul  a  comparatively  small  heater  are  preferable^  juid  in  others 
the  rt'vei-se  is  more  desirable. 

The  re([uired  i,'rate  surface  of  tlie  heater  may  be  comjmted  as 
follows  :  lirst  determine  or  assume  tlie  numln'r  of  gallons  to  be  lieated 
per  liour,  and  the  requin-d  rise  in   temperature.     Reduce  gallons 


1 

STTAA/    J 

STEAM  CO/l. 

* 

_        _               .  ,^ 

>             L 

\   ; 

/   *                                                                                               "T   ' 

1  ; 

*"     '                                                                                                                                                   i    "** 

^v?/-o     . 

\    1 

}                                  1 

"T   ,' 

* L 

^ 

s 


COLO     VMrSR 

suPPLr 


Fit:.  10. 


to  pounds  by  multiplying  by  8.3,  and  multiply  the  result  by  the 
rise  in  temperature  to  obtain  the  number  of  thermal  units.  As- 
suming a  comlmstion  of  five  pounds  of  coal  per  square  foot 
of  grat€,  and  an  efficiency  of  8,000  thermal  units  per  pound 
of  coal,  we  have 

Grate  Surface  in  sq.  ft.  =  gal^per  houO<8j  X  ri8e  in  temp^ 


.5  X  8,000 

Example. —  How  many  square  feet  of  grate  surface  will  be 
required  to  raise  the  temperature  of  200  gallons  of  water  per 
hour  from  40  degrees  to  180  degrees? 

200  X  8.3  X  a80_40)        .^  ,    , 

,  L.  =  5.8  square  feet 

5  X  8000  ^ 

In  computing  the  amount  of  water  required  for  bathtubs  it 
is  customary  to  allow  from  20  to  30  gallons  per  tub,  and  to  con- 


PLUMBING. 


29 


■t     HOT  \amt£:m 

'  -        SERVICE 


sider  that  the  tub  may  be  used  three  or  four  times  per  hour  as  a 
maximum  during  the  morning.  This  will  vary  a  good  deal,  de- 
pending upon  the  character  of  the  building.  The  above  figures 
are  based  on  apartmeut  hotel  practice. 

Boilers  with  Steam  Coils.  In  large  buildings  where  steam 
is  available,  the  water  for  domestic  purposes  is  usually  warmed  by 
placing  a  steam  coil  of  brass  or 
copper  pipe  in  the  storage  tank. 
This  may  be  a  trombone  coil  made 
up  with  brass  fittings,  or  a  spiral 
consisting  of  a  single  pipe.  Heaters 
of  these  types  are  shown  in  Figs. 
19  and  20.  The  former  must  be 
used  in  tanks  which  are  placed 
horizontally,  and  tlie  latter  in 
vertical  tanks.  If  the  steam  is 
used  at  boiler  pressure,  the  con- 
densation may  return  directly  to 
the  boiler  by  gravi  ty  ;  but  if  steam 
at  a  reduced  pressure  is  used,  it 
must  be  trapped  to  the  receiver  of 
a  return  pump  or  to  the  sewer. 

The  cold  water  is  supplied 
near  the  bottom  of  the  tank,  and 
the  service  pipes  ai"e  taken  off 
at  the  top.      A  drip  pipe    should 

be  connected  with  the  bottom,  for  draining  the  tank  to  the 
sewer.  Gate  valves  should  be  provided  in  all  pipe  connections 
for  shutting  off  in  case  of  repairs.  Sometimes  a  storage  tank  is 
connected  with  a  steam-heating  system  for  winter  use,  and  cross 
connected  with  a  coal-burning  heater  for  summer  use  where 
steam  is  not  available.  Such  an  arrangement  is  shown  in 
Fig.  21. 

The  efficiency  of  a  steam  coil  surrounded  by  water  is  much 
greater  than  when  placed  in  the  air.  A  brass  or  copper  pipe  will 
give  off  about  200  thenual  units  per  square  foot  of  surface  per 
hour  for  each  degree  difference  in  temperature  between  the  steam 
and  the  surrounding  water.     This  is  assuming  that  the  water  is 


COLD    VWTER 
SUPPLV 


Fig.  20. 


30 


ri.rMi;i\(;. 


circulating  through  the  heater  so  that  it  moves  over  the  coil  at  a 
moderate  veloi-ity.  In  assuming  the  Icmpi'nitiire  of  the  water  we 
must  take  liie  average  helWfeii  that  at  the  inlet  and  outlet. 

Kxainph\ — How  many  square  feet  of  heating  surface  will  be 
required  in  a  hrass  coil  to  heat  lUO  gallons  of  water  per  hour 
tn)m  38  degrees  to  190  degrees,  with  steam  at  5  poundii  pressure? 


f 


1 


-JC^ 


COLD  wAref) 


JL-;- 


Fig.  21. 


''It' 


-^ 


-♦^ 


T\'ater  to  be  heated  =  100  X  8.3  =  830  pounds. 
Rise  in  temperature  =  11>0  —  38  =  152  degrees. 
Average  temperature  of  water  in  contact  with  the  coils 


190+38 


=::  1 1 4  degrees 


PLUMBING. 


31 


Temperature  of  steam  at  5  pounds  pressure  =  228  degrees. 

The  required  B.  T.  U.  per  liour  =  830  X  1-52  =  126,160. 

Difference  between  the  average  temperature  of  the  water  and 
the  temperature  of  the  steam  =  228  — 114  =  114  degrees. 

B.  T.  U.  given  up  to  the  water  per  square  foot  of  surface  per 
hour  =  114  X  200  =  22,800,  and 

'''-'''  =  6.5  square  feet. 


22,800 


Ans. 


EXAnPLES   FOR   PRACTICE. 

1.  How  many  linear 
feet  of  1-inch  brass  pipe  will 
be  required  to  heat  150  gal- 
lons of  water  per  hour  from 
40  to  200  degrees,  with  steam 
at  20  pounds  pressure  ? 

Ans.  21.3  feet. 

2.  How    many     square 
feet  of  grate  surface  will  be  T 
required   in  a  heater  to  heat 
300  gallons  of  water  per  hour 
from  50  to  170   degrees? 

Ans.  7.4, square  feet. 

3.  A  hot-water  storage 
tank  has  a  steam  coil  con- 
sisting of  30  linear  feet  of 
1-inch  brass  pipe.  It  is 
desired  to  connect  a  coal-burn- 
ing heater  for  summer  use 
which  shall  have  the  same 
capacity.  Steam  at  5  pounds 
pressure  is  used,  and  the 
water  is  raised  from  40  to  180 
degrees.  How  many  square 
feet  of  grate  surface  are  re- 
quired? Ans.  5.9  sq.  ft. 

4.  A   hotel    has   30  bathtubs,   which  are   used  three  times 
apiece  between  the  liours  of  seven  and  nine  in  the  morning.     The 


Fig.  22. 


82 


ri.r.MiuNi;. 


hot-\v;it(M'  system  lias  a  storacje  tank  of  -iOO  gallons.  Allowing  20 
gallons  j)er  l>ath.  aiul  startiiiij  with  llic  tank  riill  of  hot  water,  how 
many  scjuaie  feel  of  grate  siirfaee  will  he  ie(iuirt'(l  to  heat  the 
additional  quantity  o(  water  within  the  slated  linic,  if  the  temper- 
ature is  raised  from  50  to  130  ilegrees  ?  If  steam  at  10  })Ounds 
pressure  is  used  instead  of  a  heater,  how  many  square  feet  of 
heatinir  eoil   will  he  required?  .         i  ll.t!  s(i.  ft.  o-mte. 

"^  ^  \  11  s ,  .  . 

I  lo.o  s(|.  ft.  eoil. 

Temperature  Regulators.       I  lot-water  storage  tanks    having 

special  heaters  or  steam  coils  should  he  provided  with  some  means 

for  regulating    the  temperature   of  the  water.     Fig,   22  shows  a 

simple  form  attached  to  a  coal-burning  heater.     It  consists  of  a 


Fig.  23. 

casting  about  nine  inches  long,  tapped  at  the  ends  to  receive  a 
2-inch  pipe,  and  containing  within  it  a  second  shell  called  the 
steam  generator.  (See  Fig.  23.)  The  outer  shell  is  connected 
with  the  circulation  pipe  as  shown  in  F'ig.  22.  The  generator  is 
filled  with  kerosene,  or  a  niixture  of  keiosene  and  water,  depend- 
ing upon  the  tempeiature  at  which  it  is  wished  to  have  the  regu- 
lator operate.  The  inner  chamber  connects  with  the  space  below 
a  flexible  rubber  diaphragm.  The  boiling  point  of  the  mixture  in 
the  generator  is  lower  than  that  of  water  alone,  and  depends  upon 
the  proportion  of  kerosene  used,  so  that  when  the  temperature 
of  the  water  in  the  outer  chamber  reaches  this  point,  the  mixture 
boils,  and  its  vapor  creates  a  pressure  which  forces  down  the 
diaphragm  and  closes  the  draft  floor  of  the  heater  witli  which  it 
is  connected- 


PLUMBING. 


33 


A  form  of  regulator  for  use  with  a  steam  coil  is  shown  in 
Fig.  2-4.  This  consists  of  a  rod  made  up  of  two  metals  having 
different  coefficients  of  expansion,  and  so  arranged  that  this  differ- 
ence in  expansion  will  produce  sufficient  movement,  when  the 
water  reaches  a  given  temperature,  to  open  a  small  valve.     This 


i<g 


Fig.  24. 


allows  water  pressure  from  the  street  main  with  which  it  is  con- 
nected, to  flow  into  a  chamber  above  a  rubber  diaphragm,  thus 
closing  the  steam  supply  to  the  coil.  When  the  water  cools,  the 
rod  contracts,  and  the  pressure  is  released  above  the  diaphragm, 
allowing  the  valve  to  open  and  tlius  again  admit  steam  to  the 
coil. 


34  ri.r.Mr.iNG. 


(iA3    FITTING. 

Xoxt  to  ht\itin<jf  and  vi-niilaliDU  and  |iliunl>iiinf  there  is  no 
part  of  interior  house  oonstrnrtion  re(|niring  so  nuuh  attention  as 
the  gj\s  pipini^  and  gas  fitting. 

Gas  piping  in  bnildings  sliould  he  installed  according  to 
earefnlly  drawn  specifications,  and  oidy  experienced  workmen 
should  l>e  employed.  The  gas  fitter  should  work  from  an  accurate 
sketch  plan  showing  the  location  of  all  gas  service  and  distributing 
pipes  in  the  building  and  the  locations  of  the  meter  and  shut-off 
cock.  The  i»lan  should  also  indicate  the  exact  location  and  size 
of  the  risers  and  the  position  of  the  lights  in  the  different  rooms. 

Service  Pipe  and  Meter.  The  service  pipe  by  which  the  gas 
is  conveyed  to  a  building  is  always  put  in  by  the  gas  company. 
The  size  of  this  pipe  is  governed  by  the  number  of  burners  to  be 
supplied,  but  it  should  never  in  any  case,  even  for  the  smallest 
house,  be  less  than  1  inch  in  diameter.  This  may  be  slightly 
-larger  than  is  necessary,  but  the  cost  is  onlv  a  little  more  and  the 
liability  of  stoppages  is  much  less ;  this  also  allows  for  the  future 
addition  of  more  burners,  which  is  often  a  matter  of  much  con- 
venience. Service  and  distributing  pipes  for  water,  or  naphtha 
gas,  sliould  be  from  LI  to  20  per  cent  larger  than  for  coal  gas. 
The  material  for  the  main  service  pipe,  from  the  street  to  tlie 
house,  should  be  either  lead  or  wrought  iron.  As  a  rule,  wrought- 
iron  pipe  with  screwed  joints  is  preferable  to  lead,  because  it  is 
less  likely  to  sag  in  the  trench,  thus  causing  dips  for  the  accumu- 
lation of  water  of  condensation.  Care  must  be  observed  in  the 
use  of  wrought-iron  pipe  to  protect  it  by  coating  with  asphalt,  or 
coal  tar,  to  prevent  corrosion.  The  pipe  should  also  be  well  sup- 
ported in  the  trench.  Service  pipes  should  preferably  rise  fioni 
the  street  gas  main  toward  the  house  in  oider  to  allow  all  conden- 
sation to  run  back  into  the  mains.  This,  however,  cannot  always 
he  done,  owing  to  the  relative  levels  of  the  street  main  and  the 
meter  in  the  liouse.  The  latter  should  be  placed  in  a  cool,  well- 
lighted  position,  at  or  below  the  level  of  the  lowest  burner,  which 
is  usually  in  the  cellar.  If  the  meter  is  below  the  gas  main,  the 
ser\-ice  J>ipt'  must  grade  toward  the  house  and  should  be  provided 
"with  a  drip  pipe,  or  -'siphon,"  before  connecting  with  the   meter. 


PLUMBING. 


35 


When  water  accumulates  in  the  si^jhon,  the  cap  is  removed  and. 
the  pipe  drained.  The  gas  company  usually  supplies  and  sets  the 
meter,  which  should  be  of  ample  size  for  the  number  of  Hghts 
burned. 

A  stopcock,  or  valve,  is  i3laced  by  the  company  in  the  service 
pipe,  so  that  the  gas  may  be  shut  off  from  each  building  sepa- 
rately. This  is  usually  placed  outside  near  the  curb  in  the  case 
of  buildings  requiring  a  pipe  li  inches  in  diameter,  or  larger.  In 
the  case  of  theaters  or  assembly  halls  it  is  often  required  by  law 
as  a  safeguard  in  case  of  fire.  The  meter  is  connected  with  both 
the  service  pipe  and  the  main  house  pipe  by  means  of  short  con- 
nections of  extra  heavy  lead  pipe.  A  cock  is  placed  near  the- 
meter,  and  in  large  buildings  this  is  arranged  so  that  a  lock  may 
be  attached  to  it  when  the  gas  is  shut  off  by  the  company.  Gate 
valves  are  preferable  for  gas  mains,  as  they  give  a  free  opening 
equal  to  the  full  size  of  the  pipe. 

PIPES. 
Distributing  Pipes.     The  distributing  pipes  inside  of  a  house 
are  usually  of  wrought  iron,  except  where  exposed  in  rooms,  or 


Fig.  25. 


-  Fig.  26, 


Fig.  27. 


Fig.  28. 


carried  along  walls  lined  with  enameled  brick,  or  tile,  in  which 
case  they  may  be  of  polished  bass,  or  copper.  The  chief  re- 
quirements for  wrought-iron  distributing  pipes  are  that  they  be 
carefully  welded  and  perfectly  circular  in  section.  The  first  is 
important  in  order  to  avoid  splitting  when  cutting  or  threading 
them  on  the  pipe  bench. 

All  gas  pipes  are  put  together  with  screwed  joints,  a  thread 
being  cut  upon  the  outside.  When  the  pipe  is  irregular  in  sec- 
tion the  threading  will  be  more  or  less  imperfect,  and  as  a  result 
the  joints  will  be  defective.  A  good  gas  fitter  must  examine  all 
pipe  as  it  is  delivered  at  the  building,  and   observe  the  section 


3G 


PLUMBING. 


t'itlu'r  ))y  nu'aiis  ot"  tlu>  I'vo  or  by  tlu>  usr  of  calipei's.  Plain 
wroii>,'lit-ii'on  pipi'  is  likoly  to  rust  upon  tlu'  inside,  especially 
wliere  tlio  iifas  supplied  is  imperfectly  j)uri!ie(l,  and  for  tiiis  leasou 
it  is  often  advisable  to  use  rustless,  or  galvanized  pipe,  for  the 
sniiUler  sizes. 


Fie:.  29. 


Fittings  and  Joints.  The  fittin(,^s  used  in  gas  piping  are 
similar  to  those  employed  m  steam  work,  such  as  couplings, 
elbows,  tees,  crosses,  etc.  (see  Figs.  25,  2(5,  27  and  28).  Other 
fittings  not  so  extensively  used  are  the  union,  the  flange  union, 

the  running  socket  and  right 
and  left  couplings.  Fig.  29 
shows  a  screwed  union  and 
Fig.  30  a  flange.  These  fit- 
tings  are  of  cast  iron,  or  of 
malleable  iron,  the  latter  being 
preferred  for  the  smaller  sizes. 
Fittings  may  be  either  gal- 
vanized, or  rustless,  as  in  the 
case  of  pipe,  and  it  is  especially  necessary  that  they  be  free  from 
sand  holes.  In  making  pipe  joints  the  gas  fitter  should  make  use 
of  red  lead,  or  red  and  white  lead  mixed,  to  make  up  for  any  pos- 
sible imperfections  in  the  threads ;  this,  however,  should  be  used 
sparingly  so  that  the  pipe  may  not  be  choked  or  reduced  in  size. 
The  use  of  gas  fitters'  cement  should  be  prohibited.  It  is  impor- 
tant that  each  length  should  be  tightly  screwed  into  the  fitting 
before  the  next  length  is  put  on.     It  is  always  a  wise  precaution 


Fi-.  :30. 


PLUMBING.  37 


to  examine  each  length  of  pipe  before  it  is  put  in  place,  to  make 
sure  it  is  free  from  imperfections  of  any  kind. 

Running  Pipes  and  Risers.  All  large  risers  should  be  ex- 
posed, and  it  is  desirable  to  keep  all  piping  accessible  as  far  as 
possible  so  that  it  may  be  easily  reached  ior  repairs.  All  hori- 
zontal pipes  should  be  rmi  with  an  even  though  slight  grade 
toward  the  riser,  and  all  sags  in  the  pipes  must  be  avoided  to  prevent 
the  collection  of  water,  and  for  tliis  reason  they  should  be  well  sup- 
ported. Floor  boards  over  all  horizontal  pipes  should  be  fastened 
down  with  screws  so  that  they  may  be  removed  for  inspection  of  the 
pipes.  When  it  becomes  necessary  to  trap  a  pipe,  a  drip  with  a 
drain  cock  must  be  put  in,  but  this  should  always  be  avoided  un- 
der floors  or  in  other  inaccessible  places.  When  pipes  imder  floors 
run  across  the  timbers,  the  latter  should  be  cut  into  near  the  ends, 
or  where  supported  upon  partitions,  m  order  to  avoid  weakenmg 
the  timbers.  All  branch  outlet  pipes  should  be  taken  from  the 
side  or  top  of  the  running  lines,  and  bracket  pipes  should  be  rrm 
up  from  below  instead  of  dropping  from  above.  Never  drop  a 
center  pipe  from  the  bottom  of  a  running  line ;  always  take  such 
an  outlet  from  the  side  of  the  pipe.  Where  possible  it  is  better 
to  carry  up  a  main  riser  near  the  center  of  the  builduig,  as  the 
distributmg  pipes  will  be  smaller  than  if  carried  up  at  one  end. 
Where  this  is  done  the  timbers  will  not  require  so  much  cutting, 
and  the  flow  of  gas  will  be  more  uniform  throughout  the  system. 

When  a  buikUng  has  different  heights  of  post  it  is  always 
better  to  have  an  independent  riser  for  each  height  rather  than  to 
drop  a  system  of  piping  from  a  higher  to  a  lower  post  and  grading 
to  a  lower  point  and  establishing  drip  pipes.  Drips  in  a  buildmg 
should  be  avoided  if  possible  and  the  whole  system  of  piping  be 
so  arranged  that  any  condensed  gas  will  flow  back  through  the 
system  and  into  the  service  pipe.  All  outlet  pipes  should  be 
securely  fastened  in  position,  so  that  there  will  be  no  possibility 
of  their  moving  when  the  fixtures  are  attached.  Center  pipes 
should  rest  on  a  solid  support  fastened  to  the  floor  timbers  near 
the  top.  The  pipe  should  be  securely  fastened  to  the  support 
to  prevent  movement  sidewise.  The  drop  must  be  perfectly  plumb 
and  pass  through  a  guide  fastened  near  the  bottom  of  the  timbers 
in  order  to  hold  it  rigidly  in  position.   (See  arrangement,  Fig.  31.) 


38 


rLrMHING. 


Unless  otherwise  directed,  outlets  for  brackets  should  be 
placed  '»i  foct  from  tlie  floor  except  in  tlie  cases  of  liallways  and 
lxit]iri>onis,  whore  it  is  custoiuaiy  to  jilace  them  G  feet  from  tlie 
floor.  Upris]^ht  pijn's  8h(nil(l  lu'  phinil),  so  that  nipples  which  ])r<)- 
j»'i-t    throiiLrh    tlie    walls  will    he   level;    the    nipples   should    not 


Fiff.  31. 


project  more  than  |  inch  from  tiie  face  of  the  plastering.  Lathes 
and  plaster  together  are  usually  about  |  inch  thick,  so  the  nipples 
should  project  about  1.^  inches  from  the  face  of  the  studding. 

Gas  pipes  should'  never  be  placed  on  the  bottoms  of  iloor 
timbers  that  are  to  l)e  lathed  and  plastered,  because  they  are  inac- 
cessible in  case  of  leakage  or  alterations. 

Pipe    Sizes.      All    risers    and    distributing    pipes,    and    all 


PLUMBING. 


39 


branches  to  bracket  and  center  lights  should  be  of  sufficient  size 
to  supply  the  total  number  of  burners  indicated  on  the  plans. 
Mains  and  brandies  should  be  proportioned  according  to  the  num- 
ber of  lights  they  are  to  supply,  and  not  the  number  of  outlets. 

No  pipe  should  be  less  than  |  inch  in  diameter,  and  this  size 
should  not  be  used  for  more  than  two-bracket  lights.  No  pipe 
for  a  chandelier  should  be  less  than  i  inch  up  to  four  burners, 
and  it  should  be  at  least  |  inch  for  more  than  four  burners.  The 
following  table  gives  sizes  of  supply  pipes  for  different  numbers 
of  burners  and  lengths  of  run. 

TABLE  VII. 


Size  of  Pipe. 

Greatest  Length 

Greatest    Num- 

of  Run. 

be 

•  of    Burners 

Inches. 

Feet. 

to 

be  Supplied. 

1 

20 

2 

i 

30 

4 

f 

50 

15 

1 

70 

25 

H 

100 

40 

H 

150 

70 

2 

200 

140 

^ 

.    300 

225 

3 

400 

300 

4 

500 

500 

Testing  Gas  Pipes.  As  soon  as  the  piping  is  completed,  it 
should  be  tested  by  means  of  an  air  pump  ;  a  manometer  or  mer- 
cury gage  is  used  to  indicate  the  pressure.  In  the  case  of  large 
buildings,  it  is  better  to  divide  the  piping  into  sections,  and  test 
each  separately.  All  leaks  revealed  must  be  repaired  at  once,  and 
the  test  repeated  until  the  whole  system  is  air  tight  at  a  pressure 
of  from  15  to  20  inches  of  mercury,  or  71  to  10  pounds  per 
square  inch. 

The  final  test  is  of  great  importance.  This  test  is  to  provide 
against  future  troubles  and  dangers  from  leaks  resulting  from 
sand  holes  in  the  fittings,  split  pipe,  imperfect  threads,  loose  joints 
or  outlets  left  without  capping.  If  the  building  is  new,  a  careful 
inspection  should  first  be  made  to  see  that  all  outlets  are  closed, 
then  the  valve  in  the  service  pipe  closed  and  the  air  pump  at- 
tached to  any  convenient  side-light.     To  the  same  outlet  or  an 


40  ri.i'Miuxc. 

luljm'ont  one  attai'h  tlio  mon-iiry  (•oluiini  i^Mi^'i'  usrd  by  pas  fitters, 
ami  liaviiiiif  a  ritluiim  rrom  1")  to  lit)  imlu's  in  lu'i^lit.  Care  iiiiist 
Ih?  taken  tliat  then'  aic  no  leaks  in  the  v;a(j;v  or  its  connections;  a 
tiglit-closinLj  valve  nuist  Ite  }»lace«l  Itciwcen  the  gas  pipe  and  the 
temporary  connections  -with  the  ])nnip,  so  that  it  may  he  shut  off 
immediately  after  tlu'  pump  stops,  thus  pre^(■nting  any  leakage 
thnniij^h  tiie  pump  valves  or  hose  joints.  When  all  is  ready, 
pump  the  system  full  of  air  until  the  mercury  rises  to  a  height  of 
at  least  12  inches  in  the  gage;  then  close  the  intermediate  valve 
lietween  the  pump  and  tlu'  piping.  Should  the  mercury  column 
"stand"  for  five  minutes,  it  is  reasonable  to  assume  that  the  pipes 
are  sufUciently  tight  f(n-  any  pressure  to  -which  they  will  afterward 
be  subjected. 

If  the  mercury  rises  and  falls  with  the  strokes  of  the  pump, 
it  indicates  a  large  leak  or  open  outlet  near  the  pump.  But 
should  there  be  a  split  pipe  or  an  aggregation  of  small  leaks,  the 
meremy  will  rim  back  steadily  between  the  strokes  of  the  pump, 
though  more  slowly  than  it  rose.  Should  it  rise  well  in  the  glass 
and  sink  at  the  rate  of  1  inch  in  live  seconds,  small  leaks  in  fit- 
tings or  joints  may  be  expected. 

A  leak  that  cannot  be  detected  by  the  sound  of  issuing  air 
may  usually  be  foimd  by  applying  strong  soap-water  with  a  brush 
over  suspected  joints  or  fittings ;  the  leak  in  this  case  being  indi- 
cated by  the  bubbles  blowoi  by  the  escaping  air.  Sometimes  it  is 
necessaiT  to  use  ether  in  the  pipes  for  locating  leaks,  if  the  pipes 
are  in  partitions  or  luider  floors.  The  ether  is  put  into  a  bend  of 
the  connecting  hose,  or  in  a  cup  attached  to  the  pump,  and  forced 
in  with  the  air.  By  following  the  lines  of  the  pipe,  the  approxi- 
mate position  of  a  leak  may  be  detennined  by  the  odor  of  escap- 
ing ether. 

If  the  house  is  an  f)ld  one  or  has  been  finished,  the  meter 
should  be  taken  out  and  the  lx»ttom  of  the  main  riser  capped. 
Next  remove  all  fixtures  and  cap  the  outlets.  Then  use  ether  to 
locate  the  leaks  before  tearing  up  floors  m-  breaking  partitions. 

GAS   FIXTURES. 

Burners.  Illuminating  gas  is  a  complex  mixture  of  gases, 
of  which  various  chemical   compounds   of  carljon  and  hydrogen 


PLUMBING. 


41 


form  the  principal  light-giving  properties.  Gas  always  contains 
more  or  less  impurities,  such  as  carbonic  oxide,  carbonic  acid, 
ammonia,  sulphureted  hydrogen  and  bisulphides  of  carbon. 
These  are  partly  removed  by  purifying  processes  before  the  gas 

leaves  the  works.  . 

When  the  gas-jet  is  lighted,  the  hydrogen  is  consumed  m  the 
lower  part  of  the  flame,  producing  sufficient  heat  to  render  the 
minute  particles  of  carbon  incandescent.  The  hydrogen,  m  the 
process  of  combustion,  combines  with  the  oxygen  from  the  air, 
formmg  an  invisible  vapor  of  water,  while  the  carbon  unites  with 
the  oxygen,  forming  carbonic  acid. 


Fig.  32. 


Fig.  33. 


Fig.  3-4. 


Various  causes  tend  to  render  combustion  incomplete :  there 
may  be  excessive  pressure  of  gas,  lack  of  air  or  defective  bui'ners. 
An  excess  of  pressure  at  the  burners  causes  a  reduction  of  the 
amount  of  iHumination ;  on  the  other  hand,  if  the  pressure  is  in- 
sufficient, the  heat  of  the  flame  will  not  raise  the  carbon  to  a 
white  heat,  and  the  result  will  be  a  smoky  flame.  It  therefore 
follows  that  for  every  burner  there  is  a  certain  pressui'e  and  corre- 
sponding flow  of  gas  which  will  cause  the  brighter  illumination. 
There  is  a  great  variety  of  burners  upon  the  market,  among 
which  the  following  are  the  principal  types : 

The  single-jet  burner,  the  bat's-wing  burner,  the  fish-tail 
burner,  the  Argand  burner,  tlie  regenerative  burner  and  the  in- 
candescent  burner.  . 

ne  Single^et  burner  (Fig.  32)  is  the  simplest  kind,  having 


42  ri.r.MiuNi;. 

only  one  small  hole  from   which  the  pis  issues.     It   is   suitable 
only  where  a  \eiy  small  ihime  is  re(|uire(l. 

Tht  Ji<i('it-iriu'/  or  slit  burner  (Kig.  33)  has  a  lu'mispherical 
tij»  wiiii  a  narrow  vertical  slit  i'ntm  whicli  the  gas  spreads  out  in  a 
thin,  tlat  sheet,  givin»g  a  wide  and  ratlu-r  low  llanie,  resemblinjr  in 
shape  the  wing  of  a  bat,  from  which  it  is  named.  The  eommon 
kind  of  slit  burnei-s  aw  not  suitable  for  use  witli  globes,  as  the 
tlame  is  likelv  to  crack  the  <>flass. 

T/ie  UiiioH-Jt't  or  Fish-tail  biuiicr  (^I'igs.  34   and  3o)   consists 

N/  of  a  tlat  tip  slightly  depressed  or  concave  in  the  center, 

f^^       with  two  small  holes  drilled,  as  shown  in  Fig.  35.     Two 

jl^_^      jets  of  equal  size  issue  from  these  holes,  and  by  impin- 

\         /      S^"o  upon  each  other  produce  a  flat  flame  longer  and 

p.^  narrower  in  shape  than  the  bat's-wing,  and  not  unlike 

the  tail  of  a  fish.     Neither  of  these  burners  require  a 

chimney,  but  the  flames  are  usually  encased  with  glass  globes. 

Tfie  Argand  burner  (Fig.  36)  consists  of  a  hollow  ring  of 
metal  connected  with  the  gas  tube,  and  perforated  on  its  upper 
surface  with  a  series  of  fine  holes,  from  which  the  gas  issues, 
forming  a  round  flame.  This  burner  requires  a  glass  chimney. 
As  an  intense  heat  of  combustion  tends  to  increase  the  brilliancy 
of  the  flame,  it  is  desirable  that  the  burner  tips  shall  be  of  a  mate- 
rial that  will  cool  the  flame  as  little  as  possible.     On  this  account 


.  ¥\».  36.  Fig.  37.  Fig.  38. 

metal  tips  are  inferior  to  those  made  of  some  nonconducting 
material,  such  as  lava,  adamant,  enamel,  etc.  Metal  tips  are  also 
objectionable  because  they  corrode  rai)idly,  and  thus  obstruct  the 
passage  of  the  gas.  Figs.  37  and  38  show  lava  tips  for  bat's- 
wing  and  fish-tail  burners.     Burner  tips  should  be  cleaned  occa- 


PLUMBING. 


43 


sionally,  but   care   should  be  taken  not  to  enlarge  the  slits  or 

holes. 

In  all  regenerative  burners  the  high  temperature  due  to  the 
combustion  in  a  gas  flame  is  used  to  raise  the  temperature  of  the 
gas  before  ignition,  and  of  the  air  before  combustion.  These 
powerful  burners  are  used  for  lighting  streets,  stores,  halls,  etc. 


Fig.  39. 


Fig.  40. 


In  the  incandescent  burner  the  heat  of  the  flame  is  applied  in 

raising  to  incandescence  some  foreign  material,  such  as  a  basket 

of  magnesium  or  platinum  wires,  or  a  funnel-shaped  asbestos  wick 

or   mantel    chemically  treated  with   sulphate  of  zirconium   and 

other  chemical  elements.     A  burner  of  this  kind 

is  shown  in  Fig.  39,  where  the  mantel  may  be 

seen  supported  over  the  gas  flame  by  a  wire  at 

the  side.     Fig.  40  shows  another  form  of  this 

burner  in  which  a  chimney  and  shade  are  used 

in  place  of  a  globe.     Burners  of  this  kind  give 

a  very  brilliant  white  light  when    used  with 

water  gas  unmixed  with  naphtha  gases.     The 

mantel,  however,  is  very  fragile,  and  is  likely 

to  lose  its  incandescence  when  exposed  to  an 

atmosphere  containing  much  dust. 

Tlie  Bunsen  burner  shown  in  Fig.  41  is  a 
form  much  used  for  laboratory  work.     It  burns ^ 
with  a  bluish  flame,  and  gives  an  intense  heat 
without  smoke  or  soot.     The  gas  before  ignition  is  mixed  with  a 
certain  quantity   of  air,    the    proportions    of   gas  and   air  being 
regulated  by  the  thumbscrew  at  the  bottom,  and  by  screwing  the 


GAS. 


44 


rLr.MHING. 


outer  iuIh-  U|>  ov  down,  thus  juhnitting  a  greater  or  less  quantity 
of  air  at  tlu'  o|H'iuniXS  indicated  by  the  arrows.  This  same  principle 
is  utilized  in  a  burner  for  brazini;,  the  general  form  of  which  is 
shown  in  Fijjf.  4"J.  A  llame  of  this  kind  will  easily  melt  brass 
in  the  open  air. 


Fig.  42. 

Cocks.  It  is  of  greatest  importance  that  the  stopcocks  at 
the  fixtures  should  be  perfectly  tight.  It  is  rare  to  find  a  house 
piped  for  gas  where  the  pressure  test  could  be  successfully  ap- 
plied without  first  removing  the  fixtures,  as  the  joints  of  folding 


Fig.  43. 


Fig.  44. 


brackets,  extensiofi  pendants,  stopcocks,  etc.,  are  usually  found  to 
leak  more  tiian  the  piiting.  The  old-fashioned,  "all-around"  cock 
should  never  be  allowed  under  any  conditions  whatever;  only 
those  provided  with  stop  pins  should  be  used.  Various  forms  of 
cocks  with    stop   pins    are   sliown   in  Figs.  43,  44   and.  45.     All 


PLUMBING. 


45 


joints  should  be  examined  and  tightened  up  occasionally  to  pre- 
vent their  becoming  loose  and  leaky. 


Fig.  46. 


Fig.  47. 


Brackets  and  Chandeliers.  Poor  illumination  is  frequently 
caused  by  ill-designed  or  poorly  constructed  brackets  or  chande- 
liers. Gas  fixtures,  almost  with- 
out exception,  are  designed  solely 
from  an  artistic  standpoint,  with- 
out regard  to  the  proper  condi- 
tioTis  for  obtaining  the  best  illumi- 
nation. Fixtures  having  too  many 
scrolls  or  spirals  may,  in  the  case 
of    imperfectly  purified  gas,  accu- 


Fig.  45. 


Fig.  48. 


mulate  a  large  amount  of  a  tany  deposit  which  in  time  hardens 
and  obstructs  the  passages.  Another  fault  is  the  use  of  very 
small  tubing  for  the  fixtures,  while  a  third  defect  consists  in 
tlie  many  leaky  stopcocks  of  the  fixtures,  caused  either  by  defec- 


46 


PLu:Mr>i\(;. 


tive  workmanship,  or  l)v  the  keva  becoming  worn  and  loose. 
C\immon  forms  of  hnu-ki-ts  :uv  shown  in  Figs.  4t)  and  47,  the  hit- 
ivv  hriMi:^  an  extensive  braeket.  There  is  an  endless  variety  of 
chaiuU'liei-s  nsed,  (k'pendintjc  njjon  the  kind  of  buihling,  the  finisli 
of  the  room  and  the  nnmberof  Hu^hts  required.  Fij^s.  48,  49  and 
50  show  eoniiniMi  forms  for  dwelling  houses,  Fig.  50  being  used 
for  halls  anil  eorridoi-s. 


Fis.  49. 


Fijr.  50. 


Globes  and  Shades.  Next  to  the  burners,  the  shape  of  the 
glolxjs  or  shades  surrounding  the  flame  affects  the  illuminating 
power  of  the  light.  In  order  to  obtain  the  best  results,  the  flow  of 
air  to  tlie  flame  must  be  steady  and  uniform.  Where  the  supply 
is  insufhcient  the  flame  is  likely  to  smoke  ;  on  the  other  hand,  too 
strong  a  current  of  air  causes  the  light  to  flicker  and  become  dim 
through  cooling. 

Globes  with  too  small  openings  at  the  bottom  should  not  be 
used.  F'our  inches  should  be  the  smallest  size  of  0[)ening  for  an 
ordinary  burner.     All  glass  glol^s  absorb  more  or  less   light,  the 


PLUMBING. 


47 


Fig.  51. 


loss  vaiying  from  10  per  cent  for  clear  glass  to  60  per  cent  or 
more  for  colored  or  painted  globes.  Clear  glass  is  therefore  much 
more  economical,  althougli  where  softness  of  light  is  especially  de- 
sired the  use  of  opal  globes  is  made  necessary. 

COOKING    AND    HEATING    BY    GAS. 

Cooking  by  gas  as  well  as  heating  is  now  very  common  and 
there  is  a  great  variety  of  appliances  for  its  use  in  this  way. 
Cooking  by  gas  is  less  expensive  and  less  troublesome  than  by 
coal,  oil  or  wood  and  is 
more  healthful  on  account 
of  the  absence  of  waste 
heat,  smoke  and  dust.  A 
gas  range  is  always  ready 
for  use  and  is  instantly 
lighted   by    applying    a 

match  to  the  burner.     The  fire,  when  kindled,  is  at  once  capable 
of  doing  its  full  work ;  it  is  easily  regulated  and  can  be  shut  off 

the  moment  it  has  been 
used,  so  that  if  properly 
managed  there  is  no 
waste  of  fuel  as  in  the 
case  of  coal  or  wood. 
The  kitchen  in  the  sum- 
mertime may  be  kept 
comparatively  cool  and 
comfortable.  Gas  stoves 
are  made  in  all  sizes, 
from  the  simple  form 
shown  in  Fig.  51  to  the 
most  elaborate  range  for 
hotel  use.  A  range  for 
family  use,  with  ovens  and  water  heater,  is  shown  in  Fig.  52. 
Figs.  53  and  54  show  the  forms  of  burners  used  for  cooking, 
the  former  being  a  griddle  burner  and  the  latter  an  oven 
burner. 

A  broiler  is  shown  in  Fig.  55  ;  the  sides  are  Uned  Avith  asbes- 
tos, and  the  gas  is  introduced  through  a  large  number  of  small 


Fig.  52. 


4S 


i"i.r.Mi;i\G. 


«»penintjs.     The  asbt'stos  becoiiu's  heated  and  theeffect  is  the  same 
a>  a  ehavroal  fire  upon  hotli  sides. 

Heatinjj  by   Gas.      (tas  as  a   fuel  lias  not  been  used   to  any 
Cleat  exliMil  for    ilu>  Avannini,^   of  whole    buildings,  its   apjjlieation 


c 


rSTToTTTToTT' 


^^i^ 


Fijr.  54. 


lH.-ing  usually  confined  to  the  heating  of  single  rooms.  Unlike 
cooking  by  gas,  a  gas  fire  for  heating  is  not  as  cheap  as  a  coal  fire 
when  kept  burning  constantly.  In  other  ways  it  is  effective  and 
convenient.  It  is  especially  adapted  to  the  warming  of  small 
apartments  and  single  rooms  where  heat  is  only  Avanted  occasion- 


ally  and  for  brief  periods  of  time. 
In  the  case  of  bedrooms,  bath- 
rooms or  dressing-rooms,  a  gas  fire 
is  preferable  to  other  modes  of 
warming  and  fully  as  economical. 
It  may  be  used  on  cold  winter  days 
as  a  supplementary  source  of  heat 
in  houses  heated  by  stoves  or  by  ^^»'  ^'^' 

furnaces.  Again,  a  gas  fire  may  be  used  as  a  substitute  for 
the  regular  lieating  apparatus  in  a  house,  in  the  spring  or  fall,  when 
the  fire  in  the  furnace  or  boiler  has  not  yet  been  started.  It  is 
often  emi>loyed  as  the  only  means  for  heating  smaller  bedrooms, 
guest  rooms,  bathrooms,  and  for  temporary  heating  in  summer 
hotels  where  fires  are  required  only  on  occasional  cold  days. 

The  most  common  form  of  heater  is  that  shown  in  Fig.  56. 
This  is  easily  carried  from  room   to  room  and  may  be  connected 


PLUMBING. 


49 


■with  a  gas-jet,  after  first  removing  the  tip,  by  means  of  rubber 
tubing.  The  heater  is  simply  a  large  burner  surrounded  by  a 
sheet-iron  jacket  or  funnel.  Another  and  more  powerful  form  is 
the  gas  radiator,  shown  in  Fig.  57.  This  is  arranged  with  a 
flue  for  conducting  the  products  of  combustion  to  the  chimney,  as 
shown  in  the  section  Fig.  58.  Each  section  of  the  radiator  con- 
sists of  an  outer  and  an  inner  tube  with  the  gas  flame  between  the 


Fig.  68. 


Fig-.  57. 


two.  This  space  is  connected  with  the  flue,  while  the  air  to  be 
heated  is  drawn  up  through  the  inner  tube,  as  shown  by  the 
arrows. 

Fig.  59  shows  an  asbestos  incandescent  grate,  and  Fig.  60  a 
grate  provided  with  gas  logs  made  of  metal  or  terra-cotta  and  as- 
bestos. The  gas  issues  through  small  openings  among  the  logs, 
and  gives  the  appearance  of  an  open  wood  fire. 

Hot-water  Heaters.  The  use  of  gas  cooking  ranges  makes  it 
necessary  to  provide  separate  means  for  heating  water.  This  is 
accomplished  in  several  ways.  The  range  shown  in  Fig.  52  has  a 
boiler  attached  which  is  provided  with  a  separate  burner. 

Fig.  61  shows  a  gas  heater  attached  to  the  ordinary  kitchen 


:>o 


i'i.r.Mr.i\(i. 


lx'>ilor.  A  section  thwug'h  the  heater  is  shown  in  Fig.  ()2.  This 
consists  of  a  ehamhrr  sunomuUHl  hy  an  outrr  jacket  Avith  an  air 
space  between.  (Circulation  i>ii)cs,  throui^h  \\irKli  tlic  water  passes, 
are  hung  in  the  inner  chamber  just  above  a  powi-rful  gas-burner 
phice«l  at  the  Intttoni  of  the  heater. 

A  heater  of  different  form   for   heating  huger  (juantities  of 


r 


Fig.  58. 


Fiff.  50. 


Fig.  60. 


water  is  shoAMi  in  Figs.  63  and  64.  Tliis  consists,  as  in  the  case 
just  described,  of  a  circulation  coil  suspended  above  a  series  of 
burners.  The  supply  of  gas  admitted  to  the  burners  is  regulated 
by  an  automatic  valve,  which  is  opened  more  or  less  as  tlie  flow  of 
water  through  the  heater  is  increased  or  diminished.     When  no 


PLUMBING. 


51 


water  is  being  used,  the  gas  is  shut  off  from  the  burners,  and  only 
a  smaU  "pilot  light,"  which  takes  its  supply  from  above  the  auto- 
matic valve,  is  left  burning.  As  soon  as  a  faucet  in  any  part  of 
the  building  is  opened  and  a  flow  of  ^Yater  started  through  the 
heater,  the  automatic  valve  opens,  admitting  gas  to  the  main  burn- 


Fig.  61. 


TO  FLUE 


fiOT  WATER 
OUTLET 

JRONJACKET 
W/TH 
ASBESTOS 
L/N/NG 

SHEET  /RON 
^ACKETJwmt 
ASBESTOS 
L/N/NC 


DEAD  A/R 
SPACE 


TOP  OF 
BURNEFCAP_ 


COLD  WATER 


CHAMBER 
-MO  T  WA  TER 
CHAMBER 

COLD  WATER 

-HOT  WATER 

COLO  WATER 
/NLET 


Fig.  62. 


ers,  which  is  ignited  by  the  pilot  light,  and  in  a  few  moments  hot 
water  will  flow  from  the  faucet.  The  heater  shown  has  a  capacity 
of  9  gallons  per  minute  from  a  temperature  of  65  to  130°. 

Another  type  is  that  kno^ai  as  the  instantaneous  water  heater, 
one  form  of  which  is  sho^A^l  in  Fig.  65.  This  is  made  especiaUy 
for  bathrooms,  and  will  produce  a  continuous  stream  of  hot  water 
whenever  desired.     The  heater  is  shown  in  section  m  Fig.  m,  m 


b'2 


pi.r.MniNc;. 


Avliii'Ii  A  is  llu'  i:f;is  \;ilvf,  1)  llic  \\;Ucl-  \;il\  (',  D  llic  pilot  light, 
Fl'  tlio  ImnuTs,  I  ;i  coiiiciil  luMtiiiLT  I'i'i.U'"'  •'  ;'  '^i^''  t'>  retard  and 
spread  tlu>  risin>x  heat,  K  a  iifil'mati'd  coijjjit  screen,  and  L  a 
ivvolvin<x  water  distribntcr.  In  this  lieater  the  water  is  exposed 
diivetly  tn  the  lieated  air  and  ti^asi's  in  aihlition  to  its  passini^  over 
the  heated  surface  of  the  rin<j^  I.  The  upward  arrows  sliow  tlie 
path  of  the  lieat,  and  the  downward  arrows  tlie  passage  of  the 
water. 


Fig.  63.  Fig.  64. 

GAS   HETERS. 

The  meter  sliouhl  he  jjhiced  in  such  a  position  that  it  is  easily 
accessible  and  may  be  read  without  the  use  of  an  artificial  light. 
It  is  connected  into  the  system  between  the  service  pipe  and  main 
riser  to  the  building,  the  connections  being  made  as  shown  in 
Fig.  G7. 

Diffeient  meters  vary  }>ut  little  in  the  arrangement  of  the 
diids.  In  large  meters  there  are  often  as  many  as  five  dials,  Imt 
those  used  for  dwelling  houses  usually  have  but  three.  P^ig.  68 
shows  tlie  common  form  of  index  of  a  dry  jneter.  The  small  index 
hand,  D,  on  the  upper  dial   is   not   taken   into  consideration  when 


PLUMBING. 


53 


reading  the  meter,  but  is  used  merely  for  testing.  The  three  dials, 
which  record  the  consumption  of  gas,  are  marked  A,  B  and  C,  and 
each  complete  revolution  of  the  index  hand  denotes  1,000,  10,000 
and  100,000  cubic  feet  respectively.  It  shovild  be  noted  that  the 
index  hands  on  the  three  dials  do  not  move  in  the  same  direction ; 


Fiff.  65. 


A  and  C  move  with  the  hands  of  a  watch,  and  B  in  the  opposite 
direction.  The  index  shown  in  Fig.  68  should  be  read  48,700. 
Suppose  after  being  used  for  a  time,  the  hands  should  have  the 
position  shown  in  Fig.  69.  This  would  read  64,900,  and  the 
amount  of  gas  used  during  this  thne  woidd  equal  the  difeerence 
in  the  readings:  64,900  —  48,700  =  16,200  cubic  feet. 


54 


ri.rMr.iN(;, 


OAS    nACHINES. 

Wliilo  iho  luanutaiUue  of  i,ms  for  cities  and  towns  is  a  matter 
Wvonil  the  scope  of  l;:is  littini,'',  it  may  not  be  out  of  i)laee  to  take 
up   briellv  the   operation   of   one  of  the    forms   of  gas   machines 


SERV/CS  PtPE 


MAIN  R/seft 

\ 


Ficr.  66. 


Fig.  G7. 


which  are  used  for  supplying-  private  residences  or  manufacturing 
plants. 

The  general  arrangement  of  the  apparatus  is  showni  in  Fig. 


lOTrtOtfSANO  ITMOUMND 


!^ 


FEET 


too  TVI0U3AND         I0THOU6ANO  I  THOUSAND 


Fig.  68. 


Fi«.  (VJ. 


70,  -which  consi.sts  of  a  generator,  containing  evaporating  pans  or 
chambers,  and  an  automatic  air  pump,  together  with  the  necessary- 
piping  for  air  and  givs.     The  gas  made  by  these  machines  is  com- 


PLUMBING. 


55 


bo 


50 


ri.r.MiUNG. 


numly  known  as  oarlmrettHl  air  ij:as,  bi-ing  conimon  air  imjdci^niated 
with  tlu"  vajMH-s  of  gasoline.  It  burns  witli  a  rich  hriLjlit  llauu- 
similar  to  i-oal  <,^as,  and  is  conduitcil  tliroiiuli  \>\[)vs  and  lixtnivs  in 
the  same  manner. 

Reterrim'-  to   Fij;-.  TO,  the  automatic  air  pnmp  is  seen  in  tlie 
cellar  of  the  house,  and  eonneeted  to  it  and  runniui;-   underground 
are  the  air  and  gas  i)ii)es  connecting  it  with  the  generator,  Avhich 
mav  be  a  hundred  feet  or  more  away  if  desired.      When  the  ma- 
chine is  in  operation,  the  pump 
forces  a  current  of  air  through 
the  generator,  a\  here  it  beuomes 
carbur(>ted,     thus     forming    an 
illuminating-  gas  that  is  return- 
ed  through  the  gas  pipe  to  the 
house,  where  it  is  distributed  to 
the  fixtures    iu  the  usual  way. 
The  operation  is  automatic,  gas 
being  generated  oidy  as  fast  and 
in    such  (|uantities  as  required 
for     immediate     consumption. 
The  process  is  continuous  while 
the  burners  are  in  use,  but  stops 
as  soon  as  the  lights  are  extin- 
guished.      Pow'er    f(U'    running 
the  air  compressor  is    obtained 
l)y   the    weight    shown    at    the 
right,  which  must  l)e  wound  up 
at  intervals,  depending  upon  the 
amount  of  gas  consumed.     An 
air  compressor  to  be  run  by  wa- 
ter power  is  shown  in  Fig.  71. 
The  action  of  this  machine  is  entirely  automatic,  the  supply  of 
water  being  controlled  by  the  rising  and  falling  of  the  holder  A, 
which,  being  attached  by  a  lever  to  the   valve   B,  regulates   the 
amount   of  water  supplied   to   the  wheel  in  exact  proportion  to 
the  number  of  burners  lighted.     If  all  the  burners  are  shut  off, 
the  pressure  accumulating  in  the  holder  A  raises  it  and  shuts  the 
water  off.     If  a  burner  is  ligiited,  the  holder  falls  slightly,  allow- 


Fig.  71. 


PLUMBING. 


57 


ing  just  enough  water  to  fall  upon  the  wheel  to  furnish  the  amount 
of  gas  required.  A  pump  or  compressor  of  this  kind  requires 
about  two  gallons  of  water  per  hour  for  each  burner.     The  advan- 


tages of  a  water  compressor  over  one  operated  by  a  weight  are 
that  it  requires  no  attention,  never  runs  down  and  is  ready  for 
immediate  use  at  all  times. 

The  generator  is  made  up  of  a  number  of  evaporating  pans  or 
chambers  placed  in  a  cylinder  one  above  another.     These  chambers 


oS 


ri.rMiUNG. 


are  tliviilod  by  supjwrtintif  frames  into  windiiior  passages,  which 
i^ive  an  i-xieiuietl  siirfai'e  lor  t'\  aporatimi.  l-'in;-.  72  sHdws  the 
♦jeiienitor  when  sot  wiih  a  brii-k  pit  and  nianlmK'  at  one  side.  It 
is  supplied  with  mica  gaj^vs  for  showing  tiic  aniounl  of  o^asoline  in 
eaeh  pan,  and  with  tubes  and  valves  for  distributiiiL;-  it  to  the  differ- 
ent pans  as  required.  in  small  jdaiits  the  generator  is  usually 
buried  without  the  pit  being-  provided,  but  for  larger  plants  the 

setting  shown  in 
...  1 


G*s  oun.1 

TO   f^fSC* 

or  atMjUNC 


Fig.  72  is  reconi- 
nieuded.  Car- 
bureted air  fjas 
of  standard 
quality  contains 
15  per  cent  of 
vapor  to  85  per 
cent  of  air.  A 
regulator  or 
mixer  for  sup- 
plying gas  hav- 
ing these  pro- 
portions is 
shown  in  section 
in  Fig.  73.  It 
consists  of  a 
cast-iron  case  in 
which  is  sus- 
pended a  sheet- 
Fig.  73.  metal  can,  B, 

filled  with  air 
and  closely  sealed.  The  balance  beam  E,  to  which  this  is  hung,  is 
supported  by  the  pin  II,  on  agate  bearings.  Since  tlie  weight  of  the 
can  B  is  exactly  balanced  by  the  ball  on  the  beam  E,  movement  of  B 
can  only  be  caused  by  a  difference  in  the  weight  or  density  of  the 
gas  inside  the  cliamber  A  and  surrounding  the  can  B.  If  the  gas 
becomes  too  dense,  B  rises  and  opens  the  valve  C,  thus  admitting 
more  air;  and  if  it  becomes  too  light,  C  closes  and  partially  or 
wholly  shuts  off  the  air,  as  may  be  required. 


EXAniNATION  PAPER. 

PLUMBING    PART  II. 


PLUMBING. 


Read  carefully  :  Place  your  name  and  full  address  at  the  head  of  the 
paper.  Any  cheap  light  paper  like  the  sample  previously  sent  you  may  be 
used.  Do  not  crowd  your  work,  but  arrange  it  neatly  and  legibly.  Bo  not 
copy  the  answers  from  the  Instruction  Paper  :  use  your  own  words,  so  that  we 
may  be  sure  that  you  understand  the  subject.  After  completing  the  work  add 
and  sign  the  following  statement : 

I  hereby  certify  that  the  above  work  is  entirely  my  own. 

(Signed) 


1.  A  hotel  requires  a  water  supply  of  200  gallons  of  water 
per  minute  during  a  certain  part  of  the  day.  It  receives  its 
supply  from  a  reservoir  1,000  feet  distant,  and  located  116  feet 
above  the  house  tank,  in  the  attic  of  the  building.  What  size,  of 
wrought-iron  pipe  will  be  required  to  bring  the  water  from  the 
reservoir  ? 

Ans.  3  inch. 

2.  What  is  the  best  kind  of  pipe  for  domestic  Avater  supply 
under  ordinary  conditions  ?     When  may  it  be  objectionable  ? 

3.  A  1-inch  pipe  is  to  discharge  40  gallons  of  water  per 
minute  from  a  cistern  placed  directly  above  it.  What  must  be 
the  elevation  if  we  assume  the  friction  in  the  pipe  and  bends  to 
be  equivalent  to  100  feet? 

Ans.  Ill  feet. 

4.  A  house  tank  is  situated  15  feet  above  a  faucet  uppn 
the  fifth  floor  of  the  building.  If  the  stories  are  8  feet  high,  what 
will  be  the  difference  in  pressure  in  pounds  per  square  inch 
between  this  faucet  and  one  in  the  basement? 

Ans.  17.3  pounds. 

5.  Describe  the  action  of  an  hydraulic  ram. 

6.  A  pump  has  a  steam  cylinder  6  inches  in  diameter  and 
a  water  cylinder  5  inches  in  diameter.  What  steam  pressure  will 
be  required  to  raise  water  to  an  elevation  of  100  feet,  neglecting 
friction  in  the  pipe  ? 

Ans.  40.3  pounds. 


tVJ  n.l'.MIUNG. 

7.  Explain  tlu'  action  of  the  ordinnrv  Icitchon  Ix tiler,  to- 
gt'tluM-  \\itli  the  nietluMl  of  making,'  the  eoniu'ctions. 

^  W'iial  lu-essure  \h'V  siiuiire  inch  will  lie  rt'(Hiir{Ml  to  dis- 
cliaii,'e  :2tH»  tjallons  jter  niiiniK'  throiii^h  a  horizontal  pipe  )1\  inches 
in  (lianit'ter  and  ;><>()  {vvt  Ioiilt '/      How  many  feet  head  ? 

.     ^    \  84.4  ponnds. 

9.  What  i-s  the  difference  Wtween  a  "  lift  pnmp"  and  a 
'•suction  pump"?     Descrihe  the  action  of  a  "  deep  well  "  pump. 

10.  What  is  the  greatest  dei)th  at  whieh  a  suction  pump  will 
operate?      Why? 

11.  What  two  systems  of  Avater  supply  are  commonly 
emj)loyed  ? 

12.  A  storage  tank  is  10  feet  in  diameter  and  8  feet  high. 
How  many  gallons  will  it  hold? 

Ans.  4,521.6  gallons, 
lo.  A  modern  cistern  is  5  feet  wide,  6  feet  deep  and  10  feet 
long.  It  is  desired  to  replace  it  with  a  tank  which  shall  be  8 
feet  in  diameter.  What  would  be  the  required  height  of  the 
tank?  Wliat  will  be  the  weight  of  the  water  contained  in  the 
tank  ? 

.        (  5.9+feet. 

^"^^^  i  1,8759  pounds. 

14.     A  2-inch  pipe  is  used  for  conducting  water  to  a  house 

from  a  spring  400  feet  away.     If  the  cistern  in  the  house  is  50 

feet  Ijelow  the  level  of  the  spring,  how  many  gallons  of  water  will 

flow  through  the  pipe  per  hour  ? 

Ans.  To  gallons. 
•     15.     What  are  the  principal  causes  of  accidents  in  connection 
with  a  kitchen  lx)iler,  and  what  .precautions  should  be  taken  to 
j>revent  them  ? 

l«i.  A  swimming  tank  is  supplied  with  hot  water  through  a 
hot-water  heater  similar  to  a  house  heater.  How  many  square 
feet  of  grate  surface  will  be  required  to  raise  1,000  gallons  of 
water  per  hour  from  a  temperature  of  50  to  70  degrees? 

Ans.  4.15  square  feet. 
17.      What    are  circulation  pipes  when    used   in    connection 
with  a  hot-water  supply  system,  and  how  are  they  connected  ? 


PLUMBING. 


63 


18.  How  many  square  feet  of  lieating  surface  will  be  re- 
quired in  a  brass  coil  to  heat  160  gallons  of  water  per  hour  from 
50  degrees  to  200  degrees,  with  steam  at  5  ^^ounds  pressure  ? 

Ans.  6.5  square  feet. 

19.  Describe  the  principle  and  action  of  a  gas  machine. 
How  does  a  regulator  or  mixer  operate  ? 

20.  On  July  1  the  pointers  on  a  gas-meter  stood  as  shown 
in  Fig.  1,  and  on  Oct.  1  they  had  moved  to  the  positions  shown  in 
Fig.  2.  What  would  be  the  cost  of  gas  consumed  at  $1.25  per 
1,000  cubic  feet? 


Fig.  1. 


Fig.  2. 


•21.  Describe  the  construction  and  action  of  one  form  of  hot- 
water  temperature  regulator. 

22.  A  hot- water  storage  boiler  contains  a  heating  coil  made 
up  of  42  linear  feet  of  1-inch  brass  pipe,  and  is  supplied  with 
steam  at  5  pounds  pressure,  and  the  water  is  heated  from  40  to 
140  degrees.  It  is  desired  to  remove  the  coil  and  substitute  a 
coal-burning  heater.  How  many  square  feet  of  grate  surface  will 
be  required  to  give  an  equal  capacity? 

Ans.  9.66  square  feet. 

23.  If  a  certain  heating  coil  will  heat  100  gallons  of  water 
per  hour  from  50  to  180  degrees  with  steam  at  5  pounds  pressure, 
how  many  gallons  will  the  same  coil  heat  with  steam  at  30  pounds 
pressure  ? 

Ans.  140  gallons. 


04 


IM.l'Mr.INC. 


24.  Tlie  followiiii;  diagram  reprosents  tlio  cfas  piping  in  a 
liouse,  w  itli  tlu'  iiunibor  of  lights  su[)plit'(l  Ity  tin*  dilYerent  outlets. 
Make  ilu'  >kfti'li.  ami  iiulicali-  tlic  i)ijH'  si/.t>s  for  riser,  mains  and 
braui'hfs. 


12 


•25.  Describe  the  metliod  of  testing  a  new  system  of  piping, 
and  state  how  you  would  distinguish  between  different  kinds  of 
leaks. 

2t*>.  A  house  using  coal  gas  is  supplied  through  a  2-inch 
service  pipe.  Another  house  is  to  be  built  having  the  same  num- 
ber of  lights,  but  is  to  be  supplied  with  naphtha  gas.  What  will 
be  the  required  size  of  service  pipe? 

27.  How  should  the  pipes  be  graded  in  a  system  of  gas 
piping?  How  should  branches  and  drops  be  connected  with  the 
main? 

28.  How  does  the  cost  of  cooking  and  heating  with,  gas 
compare  with  that  of  coal  ? 

29.  Xame  and  describe  the  different  types  of  burners.  What 
is  the  best  material  for  burner  tips  ? 

30.  What  is  the  best  material  for  hot-water  pipes?  What 
are  the  common  defects  in  pipes  lined  with  another  metal? 


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